Heating News – Spring 2017

Grid parity – are we there yet?

Photvoltaic panels might not be particularly efficient but they are certainly simple and cheap to run. Stick ‘em in the sun and they make electricity with no further ado. This is why over the next five years large scale PV solar for the grid will be level pegging with the existing power generation costs. So this is grid parity. As power costs rise and panels get cheaper and better, the post parity world should see PV power starting to put the brakes on energy price rises. Of course PV power won’t dominate, there just won’t be enough of it to do so, but the underlying principle will be self evident and compulsive enough to set the stalled PV train in motion again.

There is another reason to give PV renewables a boost. The nascent electric car era is going to tax the grid beyond current capacity. While petrol stations stand empty the grid will be flat out, trying to keep up. A world where the car in your garage costs virtually nothing to run is getting tantalisingly close but the Government clearly needs to act now and raise incentives for domestic PV installations.

Right now though, on the domestic front, parity is more complicated despite panel prices having fallen to around £1,000 per kWp plus the installers cost.

Take a typical 3 bed UK house with annual electricity bills of £450. A 4kWp array costing £6,500 will make a derisory £320 a year in savings and FIT income. Payback over 20 years just says ‘no way thanks,’ so no immediate evidence of parity being anywhere near.  However, before we give up, lets take another approach and scale up enough to run a small heat pump; enough to knock out half (no sun at night) the £650 annual gas bills and make the other half at about the same cost as gas would have been. A 6kWp array making around £450 a year and costing £8,500 to install plus another £5,000 for the heat pump makes a total cost of £13,500 for an effective return of £875.

That 6.5% return looks a bit more interesting! What if we took advantage of these crazy low borrowing rates and borrowed the £13,500 from, say, Sainsburys for an annual payment of  £2,267over 7 years? We can expect a little help from the Renewable Heat Incentive payments for 7 years applied to the air source heat pump – like £770 a year according to the Ofgen example.

Deducting the £875 savings and the RHI £770 you effectively pay £622 for seven years until the loan is all paid off. You are then left with £875 a year in benefits (and rising) for as long as the kit lasts, which should be a good 13 years. This looks like a sensible way to prepare for a comfortable retirement; almost like a pension. Put an electric car in the garage and another major cost will be eliminated.

Very attractive RHI incentives are also available for solar thermal panels (although making DHW only). £220 a year in the Ofgen example. Even more noteworthy is the emphasis on the more expensive ground source heat pumps where the example returns jump up to £2,100 a year for 7 years. They not only pay a much higher tariff (19.64p/kW vs. 7.63) but the higher COP of the GSHP affects the calculations in your favour. The calculations are based on your energy demand taken from your EPC certificate and you can easily do them yourself.

My definition of grid parity is when it pays to borrow money to buy solar PV. On that basis I’d say we are still some way off but the RHI incentives are making combined systems worth considering.

You can see these and other ideas explored more on an eco-house design here. This house is designed to be virtually off grid and able to provide a separate living unit for grannies or Airbnb paying guests.

To delve deeper into eco-energy concepts you might like to look on Amazon where you can download, for Kindle, my book ‘Dream House – Down to the details’ £2.45. Details

 

For the Italian readers – low borrowing rates – time for a heating makeover.

There is no getting away from the fact that the cost of heating in Italy is a major issue. The wood/solar solution is usually the answer but the high installation cost often leaves householders trapped in an expensive rut. OK, so lets go back to Sainsburys to borrow £8,500 for a perfect solar/wood stove/heatbank solution to be delivered to your door. £152 a month (£1,824 a year) for 5 years gives you a delightful system that will run for around €1,200 a year. This is deluxe kit. The best stove, the best heat bank and a huge 3 panel solar array.  You’ll be warm as toast and there will be masses of hot water. The heating even works in a power cut so you will be safe and even able to cook if disaster strikes. Sorry to keep flipping currencies, but this means that if your heating bills exceed £3,000 a year then it’s time to have a think about a makeover. So many owners of Italian houses spend double this but there is no need to be one of them. If you need a hand to figure out if a makeover would work for you, just get in touch on the contact form below.

A plug for Italian eco-heating.

Heating in Italy

Word is getting round about eco-heating in Italy. See The Daily Telegraph article here.

In praise of the Casio solar watch.

This story started at the clock museum in Greenwich. I was admiring John Harrison’s (he of the Longitude prize) sea going clock, with all the elaborate pendulums and springs, and realised that his strange machine was more accurate, even at sea, than my £1,000 Breitling Aerospace titanium watch. Now I loved that watch but this was too much to bear so it was sold straight away to someone in the office and five of us there did a deal to get some Casio Waveceptor Toughsolar watches at £130 each.

These watches tune in to the atomic clock at Rugby each night so they are absolutely accurate. The expression ‘What do you make the time?’ is redundant, the time is what it is, period. The first pip goes exactly when the second hand hits the top, even when the clocks change twice a year the hands wind an hour on or off during the night. There is no knob on the right to adjust the time (obviously) and this facilitates the sport of asking owners of expensive watches why they have a knob on their watches. ‘To adjust the time – really?’

The face of the watch hides a solar panel and the metal strap lasts without wear so there are no tedious battery and strap replacements (£30 and £70 respectively on the Breitling).

All this was 10 years ago and the watch, being waterproof, has almost never been off my wrist. It just ticks away faithfully and relentlessly, over 315 million ticks so far, a number of tiny mechanical jolts that beggars belief.

So after the first ten year stint old watch, I salute you.

Small, affordable eco-house

State of the art eco-house is easy and cheap to build.

Check Google images for tiny house, small house, eco-house, green living module or just a modern house. See anything you could imagine building reasonably cheaply and easily then enjoy living in?

Here is something to stir the imagination, a concept sketch of the Original-Twist Eco-house. And this is not just an eco-house by name; it is a thoroughly engineered, practically off grid living module where the technology comes first and the house is made to fit it.

On the first floor a massive structurally open space gives adaptable options.  There is space to the left for a huge kitchen diner (7m x 3.5m) or a smaller kitchen and a bedroom/study. Next comes the massive living room (5m x 5m). The raised bedroom platform (4m x 5m) follows and off that a bathroom and an office or child’s bedroom. These are exceptionally large and impressive spaces and with some expensively extravagant oak frames supporting the roof they are characterful too. Everyone loves heavy rustic looking beams and that ‘barn conversion’ look.

Bye the way; as a protest against flimsy curtain rails there would be heavily mounted industrial Henderson tracks. Even Tarzan could be trusted to draw the heavy curtains across the windows or the bedroom section.

First floor layout

On the ground floor a properly large garage at one end and a full height kitchen conservatory at the other, contain a variable layout of rooms to make a separate living unit. Thus the upper and lower floors combine to make a family house or each make fully independent living spaces. There would be no difficulty making a Granny annex or securing some rental income to pay back some expenses. The foundations for the conservatory should be laid from the start to make it easy to add that on later.

Care has been taken to keep the house very basic and thus avoid unnecessary overspends. We want wonderful living spaces and enough cash left over for something special in the double garage. The simple construction suits ICFs (giant foam Leggo blocks with concrete poured in). It makes more sense to stick to ICFs all through; one contractor, less interference and anyway the clever flooring solution that comes with Quadlock ICFs is worth having. The extra thermal mass is a big plus point and also gives good soundproofing between floors. ICFs are particularly suitable for the wooden cladding shown here although the choices are almost endless.

Another cash preserving strategy will be to delay a whole list of things until after moving in.  The sooner you move in the sooner you stop paying rent somewhere else? The ground floor kitchen/conservatory, home cinema, and all the solar panels can all wait until later and the rent you save will help pay for them. Self builders will appreciate the idea of finishing one floor and living-in to finish the other.

A house designed for the hard times of ex-growth Britain deserves a catchy name – we’ll call it The Brexit.
The side and rear overhangs allow the house to fit into a small plot. It can be built to within a whisker of the boundary and yet you can still walk round the outside. The balcony at the front echoes the overhang to give a pleasing uniformity.

The Brexit is quite small which leaves something in the budget for all the latest mod cons like the home cinema, that car in the integrated garage and of course the eco-kit  and the heat pump pod in the garden. It may look fairly conventional (planners note) but the eco-credentials of this house are exemplary.

The south side has plenty of glass which adds to the feeling of space and allows for enough solar gain to take us into passivehause territory.

Of course the eco-technomologicalness will be state of the art, not just token gestures as in many eco-houses but the highest expression of the art. The 24 Sunerg hybrid solar panels actually dictate the size and shape of the roof and the roof trim panels are fixed directly to the panels (PV and wet solar are both 2m x 1m).  4 of the panels on the steep roof will be wet to give a massive 8sqm to feed the Original Twist twin tank heat bank design. If you are involved in creating anything remotely like an eco-house you should study this system here. The other 20 panels give a nominal 6kWp and a real 2-3kW in the winter to run the little air source heat pump which also does some neat heat recovery from the house and uses some ground heated air too.  Batteries make a huge UPS which largely makes the mains supply more like a backup especially if combined with the batteries in the electric car. The Brexit is designed to be future proof as much as possible. More detail can be found in the e-book ‘Dream House – Down to the Details’ here. Don’t start any project without investing £2.45 on this book.

To convert the living space into a dining room the table comes up from the floor – (see the design here)…… the TV disappears behind a roller cover and the sofa glides back into the recess behind it; fanciful maybe but it makes excellent use of the space and easily accommodates large dinner parties. The sofa mechanism is quite simple with the sofa parking on top of the cover door when it is deployed. The table concept is equally simple but pretty spectacular in action and the small extra cost effectively produces an extra room.
With all the clutter cleared away there is plenty of room for partying with the ‘bar height’ raised platform making a safe place to put food and drinks. This house really is an entertaining machine.

And what a super house to start the day in.  A cuppa in bed on your lofty bedroom, as the heavy curtains automatically retract you watch the morning news on the big screen; time for showers then a sunny breakfast downstairs before nipping through to your dream car. The garage doors rise automatically and you are off on your day.

How much roughly? 188 square metres at £800 is around £150,000. £25,000 for the eco-tech and heating systems, so maybe £180,000. Call it £200,000 plus the plot cost. Looks like a lot of good living for the money, and don’t forget, this versatile house has considerable earning power and almost no running costs. Think clever, think Brexit.

Eco-heating system for heat pumps

Ultimate Eco-heating system

Ultimate Eco-heating system

Ecological heating (Eco-heating)

The Eco-heating goal is simple.  To use free or green energy (solar/wood) so effectively that expensive fossil fuels, energy bills and the carbon footprint disappear.  The only reason to be attached to the grid is to supply it; well not quite, we might need the grid to smooth any fluctuations but we certainly don’t need much of it.

Modern houses are well insulated and need a lot less energy to run than before and a few technological advances have made Eco-heating absolutely viable.

As a starting point, a tank of water – a heat store – is required to integrate various heat sources and demands. A single heat store makes an excellent heating system but two tanks are altogether much better, especially when it comes to integrating solar and a heat pump. So much more is easily optimised with twin tanks that this is the future for eco- heating systems.

Before you start to plan your own ultimate heating system there are a few points to consider:-

Photovoltaic panels (PV) rarely produce their rated output.

On a bad day they produce only around a third of their rated output – say 50W per square metre.

Background electrical demand (fridge, computers, lights, TV etc.) can often be as high as 1kW

The PV panel array will have to be much bigger than the usual 4kWp (16 panels) for there to be enough surplus power to make an eco-house.

 A heat pump takes electrical power and delivers around 3 times as much more energy in the form of hot water. This engineering miracle might be the core of the system, but …

The power multiplier

The power multiplier

…. the times 3 trick (coefficient of performance or COP) is highly variable, and depending on outside temperatures and delivery temperatures, can vary from 2 to 5. The manufacturer’s quoted COP is for very specific conditions which you might not see very often.  Even the quoted power output of a heat pump will not be reached when it is very cold outside.

 

Air source heat pumps are a better choice than ground source heat pumps

They cost less and are easier to install. For the full argument see:-

https://originaltwist.com/2015/02/27/air-source-heat-pumps-and-the-renewable-heat-incentive/

https://originaltwist.com/2014/03/19/heat-pumps-in-southern-europe-air-or-ground/

PV + heat pump = Free heating

A heat pump on a COP of 3 redresses the shortcomings of the PV panels on that bad day, so a PV panel and heat pump combination can deliver 150W per square metre of panel and two or three times as much on good days.  This energy, in the form of hot water, can be delivered to underfloor heating which usually uses about 50W per square metre of floor and never more than 100W (which would make your feet hot).  So, for a rule of thumb, the PV panel area should be about half the heated floor area, plus up to another 20 square metres to cover background consumption.  Therefore, most self-supporting Eco-houses are likely to have up to 40 PV panels on the roof; a lot.

Air source heat pumps run much more efficiently during the day when the air is warmer.

Not only more efficiently but combined with PV panels much of the daytime energy produced is free.  Obviously big PV and a slightly oversized heat pump can produce excess energy which could keep the heating on after the sun goes down. The surplus energy will need to be stored in tanks of water – big ones.

A house with high thermal mass will also work better in this respect.

Solar thermal panels are much cheaper and much more efficient than PV.

OK, they don’t make electricity nor do they print money like PV can.  However, given some sun, they do produce very hot and free high grade water heating, so the system should have an excess of them.  Massive solar is hard to manage and here again big tanks are part of the answer.

Solar thermal panels can be made to run more efficiently.

Solar panels can only heat a tank that is cooler than they are. In winter when the tank is usually already hot and solar is weak the panels often stop working altogether.  Given 2 tanks however – one hot and one cool – the panels will run almost daily throughout the year and this dramatically improves effective panel efficiency. The Original Twist solar stripper circuit decides which tank, or both together, can use the available heat more favourably.

A pair of 500 litre tanks are only 2m high and together under 1.5m wide.  Tanks up to 500 litres can be made of light gauge steel so they are relatively cheap and easy to handle.

Gas boilers – not quite redundant

On the coldest night the heat pump with reduced power output and the lowest COP might be struggling, especially if it was sized within the limitations of single phase electricity. A gas boiler is a towering powerhouse by comparison, producing instant high grade heat at a low price. Hot water recovery times are just minutes and a shower could run hot forever if required.  For a larger eco-house, a gas boiler for very occasional use makes sense and ensures that there are no compromises to comfort whatsoever.

Under floor heating is not always best.

Bedrooms need to be heated quickly, often briefly, and preferably not with a hot floor under the bed.  Floors of upstairs bedrooms are often reasonably warm already because they are above rooms which are heated all day so paying to heat them more makes little sense.  The answer for bedrooms is the fan-coil unit which is essentially a hot water powered fan heater. Not only will they heat the room in minutes, but connected to a suitable heat pump they will cool it as well.  Air quality can be enhanced by UV purification, a boon to asthma and hay fever sufferers.

Towel rails are different.

After your shower the towel rails will need to be on long after you have got up or gone to bed. The timing and heating requirements for towel rails is completely at odds with the rest of the system and they need to be properly integrated with a dedicated supply.

Wood burning stove

Mankind has been sitting round fires for thousands of years; for many people it is unthinkable not to have a real fire in the home.  We are talking eco-heating here so an open fire is out of the question but a good stove is much nicer to live with anyway.  A big stove with a big view of the flames will be too hot for most rooms so it will need to be connected to the water tanks in order to take some heat away. That’s no bad thing as high grade hot water is not so readily produced by the heat pump. A well matched stove can usually cope with all the hot water and heating needs which relegates the heat pump to an auxiliary role and certainly means that smaller heat pumps can be considered.

Controls

Although it is not an absolute requirement, the eco-heating system will work much better with a home automation system such as the Z-Wave Vera. The hot water circulation system, for example, can be activated by sensors in the bathrooms when they turn on the lights. Temperature sensors and relays to activate pumps and valves can be found in the Qubino Z-Wave flush relay which has a built in temperature sensor.  The destratification routine (see below) can be triggered by the integrated temperature sensor and the short pump runs monitored by a controller which easily copes with ‘if this then that’ situations.

Efficiency – the humbug

Just a reminder; the sun is free. There is no need to agonise over panel efficiency. The most reliable flat plate thermal panels are cheap so if you need more power just add more. Anyway, during the hotter months they are more efficient than evacuated tube types.

To store daytime heat pump production, the target temperature needs to be raised and that is relatively inefficient compared with driving the under-floor heating directly. Again the pump is usually running free, courtesy of the sun, so the efficiency doesn’t matter.

 

The Eco-heating system

Considering all of the above your ultimate Eco-heating system should be like this:-

Much of the suitable roof surfaces will be covered in PV and thermal solar panels.

An air source heat pump

Air conditioning via the heat pump

Under floor heating on the ground level

Fan-coils in bedrooms

Fan-coils in some living rooms for air conditioning

A gas boiler (optional)

A twin tank heat store system. Up to 500 litres x2.

A wood burning stove connected to the tanks

A system that can optimally integrate all of the above with no compromises at all is a tall order.  Here it is though; the Original Twist Eco-heating System.

Two tanks it is then – one hot one cooler – but with some sound thinking around the connections to the heat sources:-

Domestic hot water delivery.       

Fresh and pressurised water is heated by the hot tank via a plate heat exchanger – standard heat store practice. However, as the hot tank water will be rather modestly heated by a heat pump, the ability of the plate heat exchanger to cope with icy fresh water can be compromised. So to warm the incoming water it first runs through an internal coil in the cooler tank before getting to the external heat exchanger on the hot tank. The pre-warming is not mission critical so there are no controls or pumps to worry about. It’s just a passive coil in the cooler tank.

Back on the hot tank the usual temperature limiting valve – anti scalding – has been dropped in favour of electronic regulation of the heat exchanger flow pump with a Steca  TF A603 MC+ controller. This slows down the pump to give a precise output temperature and so leaves more water at the top of the tank ready for more showers. The flow out of the heat exchanger and to the bottom of the tank is also cooler which aids cooling of the solar coil.

Water circulation around the house is essential to save water wastage and eliminate that annoying wait for hot water.  The same Steca controller also regulates the circulation pump speed.

Preheating the domestic hot water via the cool tank not only makes a heat pump a feasible hot water maker but it also raises the efficiency in a subtle way. The water in the cool tank is heated just enough to supply the floors and fan-coil units and a heat pump does that very efficiently. Blending this cheaper energy into the hot tank system gives an efficiency boost and also allows the hot tank to be maintained a little cooler which gives another efficiency boost.

Other potential heat inputs to the hot tank (wood, solar and gas) are not disruptive to stratification so hot water drawn from the top is always ready for service.

The solar stripper circuit.

Solar thermal panels connected to a hot tank which is already hot – as it would be with a stove or heat pump keeping it ready for hot water delivery – will be effectively switched off in weak sunlight.  But given access to a cool tank they will leap into action at the first glimmer of sunshine, practically every day of the year. Low temperature solar flow addresses the coil in the cool tank first but as soon as it is hot enough it is switched to the hot tank. The flow emerging from the hot tank is usually still very hot so the return flow to the panels goes back via the coil in the cool tank to strip out some more energy.  The panels not only run throughout the year but more efficiently due to a cooler return feed.

The Original Twist Solar Stripper Circuit achieves all this with a special 3 port Coster valve that does not interrupt flow as it changes over. The solar pump is started by the cold tank sensor and everything is managed by the Steca TR 603 solar controller which also modulates the pump speed to keep flow temperatures up.

With two solar coils in use, a bigger solar array can be used without resorting to the absurd remedy of using an external plate heat exchanger and circulation pump. Absurd? Imagine sunrise, the panels and the pump start up, the tank is destratified and your morning shower is there no longer. Dooh!

 

Heat management

With high grade heat sources connected – a wood burning stove and solar – the hot tank can get very hot. High grade heat is a valuable commodity so the system hangs on to it as long as possible but excess energy will have to be moved eventually. The system does this in 4 stages, each triggered by a cascade of temperature levels.

Destratification  – First the pump for the hot water plate heat exchanger is activated for short bursts. This moves hot water down the tank and effectively increases its capacity.  The process is limited to the maximum return temperature a wood burning stove can tolerate before the back boiler starts to kettle.

Blending the tanks – If surplus energy is still arriving, a valve connecting the hot and cool tanks opens and the cool tank starts to warm up via a thermosiphon. In this way a wood burning stove would provide for masses of hot water first and then go on to address the central heating. The valve sets to open in a power cut and is controlled by the overheat stat for the hot tank.

Overheat thermostat 2 – In the unlikely event of the cool tank reaching 70 degrees, the overheat thermostat starts the heating pump to dump heat to the heating system or a purpose heat-dump fan-coil.

Power free heat dump – As a last resort, and in the case of a power cut, a power free valve in the hot tank is activated to flow cold mains water through a small coil and send energy down the drain.  It is hard to envisage a system where this would really be required but the option is there.

Heat pump integration

The floors pump and the fan-coils pump first draw water from the tank, the repository for free energy. The heat pump runs when the tank temperature becomes too low and then the flow goes directly to the floors or fan-coils. The latter can only be achieved if the heat pump circulation pump flows slightly more than the demand pumps and there are a couple of ways to ensure that. When the heat pump is running under PV energy during the day it will top up the tanks or supply heating depending on demand. Heat pump set points to suit fan-coils or floors will be triggered by the relevant circulation pumps and by the PV output.

Controls

You might imagine that a sophisticated control system would be needed but that is far from the case as many of the functions are independent of each other with only temperature levels causing any interaction.  For example, the circulation pumps for floors and fan-coils are only activated by programmable thermostats and the latter do not call the heating.  The heat pump is timed and only tops up the tanks if temperatures fall enough to call it, otherwise the wood and solar do the job. Destratification and blending are all independently triggered by temperature levels.

Simplicity is a major benefit. Should any problems arise there is no need to call in a specialist expert.

Who makes it?

In the first instance I will help you to specify and match the various elements of the system so that a bespoke specification is readied for production by the British manufacturer.

The system is based on a standard heat store with a few additions and those additions contain nothing new or untested.

Despite the simplicity this is the absolute cutting edge of Eco-heating systems.

Pre-wired and plumbed this is a quick and cost effective way to solve all your heating issues. The successful integration of wood and solar means a smaller and less expensive heat pump can be used with fewer P.V. panels to drive it. Considering all these savings and minimal running costs the Original Twist Eco-heating System is what every new Eco-house needs.

To see if this, or a single heat store, would be suitable for you just use the contact form and we can discuss your requirements.

 

The Original Twist Eco-heating system

Features summary

Stainless steel tanks – should last a lifetime

Total of 1,000 litres for energy storage

One cool tank for virtual stratification.

Mains water pressure is maintained but tanks are unpressurised

No hot water is stored – legionnaire’s avoidance

2 stage hot water heating for heat pump compatibility

130Kw heat exchanger for hot water making – more if required

Hot water circulation

Anti scalding

Suitable for solar input of up to 14kW

Solar stripper circuit for dramatically enhanced panel efficiency

Special large ports for wood burning stove gravity connection

Extra sensor pockets for home automation compatibility

DHW prioritised with energy overspill to heating

Condensing gas boiler optimised – controlled return flow temperature

Heat pump optimised and compatible with other heat sources

Heat pump efficiency raised through extra daytime running

3kW immersion for backup heating

4 stage safety system for energy control

A mix of under-floor heating, towel rails and fan-coils can be used

Fan-coils and a suitable heat pump can give air conditioning

Eco Heating News

Heating News  Jan 2016

An Eco-house restoration case study

New Controller from Z-Wave and a chip upgrade

Clearview stove price check

Ultra cheap LED bulbs

£4 automated kettle

Eco restoration case study

We were constructing our dream house for a family of four. A total roof off renovation and extension of a 140 square metres, stone-walled Italian farmhouse in the hills near Città di Castello.  Heating is a big issue in Italy and having rented a farmhouse for a number of years we knew first-hand how brutal the winters can be!  This is how we met that challenge.

Judging by the freezing house we rented and friends’ houses, we knew we had to avoid the miserable conditions they suffered along with huge heating bills.  Insulation was an essential first step and with the help of architect Marco Carlini we built a ventilated roof that was almost over the top in efficiency terms, but then there is no such thing as too much insulation.  Plenty of insulation under the floors ensure that the heating is pretty responsive – by making sure it goes up into the tiles and not down into a freezing cold concrete slab underneath (yes, heat travels in all directions!)

Heating with gas was never an option, a pellet stove offered expensive fuel with noise and maintenance. What we needed was to burn wood (the cheapest source of energy) and add free solar power to that; how to integrate all these things workably and efficiently was not at all clear but fortunately eco-heating consultant Patrick Littlehales stepped in with a total solution which was clearly going to tick all the boxes.  After a whole day in a heating seminar all the clouds lifted and the final system was not only obvious but remarkably simple too.  Basically it’s a big tank of water (Specflue 500L heat bank) a Clearview 750 stove with back boiler and an extra big set of solar panels. Probably the one thing that brings this off is matching the overlap of the power curves as winter heat (wood) gives way to summer solar – when the curves overlap you don’t need another source like gas to fill in.

Patrick is a great exponent of ZERO COST heating and we loved that idea. It was simple enough; photovoltaic solar panels on our new roof would make enough money to pay for wood and minimal electricity.  To catch a good tariff Marco Tufi from IWT Engineering put the panels on the old roof and then they were later transferred to the new roof a year later when it was ready.

Going into our second winter the system has met all our expectations – we just love it.  The 14kW stove is a focal point and is a joy to operate. It easily heats the house (radiators/UHF upstairs and UHF downstairs) and provides masses of hot water. The tank has a 3kW immersion heater and I fitted an additional 2kW one to use some of our free electricity.  The oversized solarthermal array has been startlingly successful.  Three panels from Sunerg sit on the bank by the house (fantastic bargain – thank you Patrick). They are angled steeply to catch the winter sun and tame the fierce summer sun; the resulting flat and wide power curve gives remarkable performance in the shoulder months, even into January.

Living in the countryside brings the risk of being stranded in the snow and power cuts – a potentially deadly combination.  Our stove and tank are simply connected with no pumps so we can cook on the top (we do anyway) and keep warm come what may.  Not many homes have that level of security. There’s no risk of our heat bank overheating since it thermosiphons perfectly to two upstairs radiators – slowly dumping the heat – an additional, power-free way of heating!

Was it hugely expensive?  Yes and no.  The up-front equipment costs were certainly weighty but offset by the ease and speed with which the heat bank and all its pumps etc. was installed. In this respect it was practically free.  The fact is that the investment will be paid back relatively quickly (Photovoltaic the longest in around 7 years) and after that we’ll live almost cost free in our dream house – what’s not to like?

 

A new controller from Mi Casa Verde as Z-Wave gathers pace.

Mi Casa Verde have just released their Vera Plus smart home controller for a mere £140.  For anyone considering starting a home security system, with the option of a host of home automation features thrown in, this is really good news.

Vera Plus lets you easily set up, monitor and control lights, cameras, thermostats, door locks, sensors, alarms, smoke detectors, lawn sprinklers and more from practically any brand. VeraPlus supports 1400+ devices from all major brands and works with many popular devices using Wi-Fi, Z-Wave, ZigBee, or Bluetooth.  All this is unified under one single app which runs on any tablet or smart phone.  You can buy Vera Plus from http://www.vesternet.com/ and get plenty of advice at the same time.

Z-Wave itself is moving on with the release of a third generation of the chip found in every device. This gives better range between devices which in turn extend the range further in a meshed network.  Extended range means that security sensors can be placed further out from your house to mark out your first perimeter.  I love the idea of having a table lamp give a subtle flash when guests are arriving – it’s not all about the burglars.

Multiple functionality is emphasised in the new chip so now if you buy a motion sensor it is likely to measure temperature and light levels too; all useful features when controlling lights or heating.  Another example is the Fibaro flood sensor which includes a tilt sensor (so you know if someone moved it), temperature sensor, a siren, a light, a built in Z-wave network range tester.  If you leave your house unattended for long periods, you might feel happier if you had popped one of these on the floor.

There are now 250 firms making Z-Wave products, so you might start off with a controller and a couple of sensors, just to get the hang of it, but after that adding more features is a never ending journey.

Clearview 750 prices.

I’ve had a couple of enquiries recently so here is the latest quote from the factory for the ever popular 750 flat top with the 7kW back boiler.  N.B. When I’m supplying tanks and stoves I always try to round down the prices and they come with loads of free advice too.

Stove              £1,782

Back boiler       £312

Colour               £60

UK delivery        £49

Total                  £2,203

You might ask why the Clearview is so popular when it is also rather expensive.  Well there’s robustness for a start. Folded up quarter inch plate is tough and indeed rather weighty; it takes 4 strong men to move one.  Then there’s the clip in – and easily replaceable –  stainless back boiler. A leaky, crack prone cast iron stove with integrated boiler might save a few bob now but you might have to buy a couple more during the lifetime service of a Clearview.  A cracked stove could ruin your floors and rugs and leave you without heat for weeks. A fate to be avoided at all costs. Personally I prefer the plain looks and the huge glass doors giving a great view of the fire.

 

LED light bulbs – cheaper than cheap!

Take a look at http://www.trillion.co.uk and check out a range of LED bulbs starting from £1.50!

Now that’s just as cheap as any other type of bulb so there is no reason to hang back.  And yes you should bin any other bulbs immediately in favour of LEDs which consume about a tenth as much as an incandescent bulb.  An old 60 Watt bulb running 2,000 hrs a year (if it lasts) will cost £26 to run in Italy and £14 in the UK so the cost of the bulbs is becoming trivial compared to the running costs.  I’ve just bought a shed load of bulbs from Trillion and they seem fine with the warm white ones (2,700K) a good colour.

£4 automated kettle

Do you make the early morning tea?  Don’t you hate standing around in the cold waiting for the kettle to boil?  £4 at Amazon for a square timer plug will change your life.  Last thing at night, fill up the kettle and leave it turned on. Set the timer to come on when you wake up and only get out of bed when you hear the kettle click off. Nice.

If you’d like to talk about heating, cheap pool pumping, solar panels, stoves, tanks and everything else please use the contact form here.

Tiny Affordable Eco house

Tiny Affordable Eco house

view - South side

view – South side

Eco house from the end showing garage door

Eco house from the end showing garage door

Check Google images for tiny house, small house, eco-house, pod, green living module or just a modern house. See anything you could imagine building very cheaply then living in?
Here’s the Original Twist idea of a simple modern looking house which, by using blocks or ICFs for the first floor and SIPs (structural insulated panels) on top, is quick and correspondingly cheap to make. It is also quite small which leaves something in the budget for all the latest mod cons like the home cinema, a nice car in the integrated garage and of course the eco kit – 24 solar panels and the heat pump pod in the garden.
The actual building is conventionally cubic, clad in vertical wood, with all the metallic looking curvy edges added on later. The edges conceal wires and pipes and are made of polystyrene or zinc covered forms. The upper south side is nearly all glass which adds to the feeling of space and allows for enough solar gain to take us into passivehause territory.
Small it may be but it is huge inside with the main living area 6m x 10m and a similarly massive room downstairs, both with cavernous ceilings. The raised bed platform gives a visual separation from the seating area and allows the big room to be a sitting room, bedroom and dining room all in one go. It will feel like a large expensive modern house but without the heavy price tag.
The main seating backs onto the big step and faces the partition wall which neatly houses a huge 4K TV, and all the usual kit, beneath a roller tapestry. This prefabricated wall incorporates storage on the reverse side and integrates all the gear for home automation, security and communications.

To convert the living space into a dining room the table comes up from the floor – (see magic table on http://www.originaltwist.com)…… the TV disappears, the bed tips up and away and the sofa glides back into the recess behind it; fanciful maybe but it makes excellent use of the space and easily accommodates large dinner parties. The sofa mechanism is quite simple with the sofa parking on top of the cover door when it is deployed.
With all the clutter cleared away there is plenty of room for partying with the ‘bar height’ raised platform making a safe place to put food and drinks. This house really is an entertaining machine.
There is a doorway either side of the big screen; one for the upstairs loo and the other to the kitchen. The generally high ceilings allow for an optional extra bedroom over the upstairs kitchen, accessed by a stairway along the back wall. It has to be very light and airy looking to preserve the cube like look of the main structure.
The house is suited to be built on a sloping site so access to the first floor would come from that level and ideally via a glass entry vestibule to the front door on the wall opposite the big glass south wall.

Conservatory, kitchen, bedroom, car - what else do you need?

Conservatory, kitchen, bedroom, car – what else do you need?

Downstairs the large breakfast room enjoys a wrap around conservatory and incorporates a second small integrated kitchen. Doors to the rear lead to an en-suite bedroom, a loo and the garage.
The daily grind won’t seem so bad when you start with a cuppa in bed watching the morning news then a shower (in the small shower-room on the bed level) before going downstairs to a sunny breakfast before nipping through to take your Porsche off to work.

Of course the eco-technomologicalness will be state of the art. The 24 Sunerg hybrid solar panels actually dictate the size and shape of the roof and the red trim panels are fixed directly to the panels (PV and wet solar are all 2m x 1m).  4 of the panels on the steep roof will be wet to give a massive 8sqm to feed my own twin tank heat bank design – my speciality. The other 20 panels use micro-inverters to give a nominal 6kWp and a real 2-3kW in the winter to run the little air source heat pump which also does some neat heat recovery from the house and uses some ground heated air too.  Batteries make a huge UPS which, combined with the batteries in the electric car, largely makes the mains supply more like a backup.

Eco pod

Eco pod

At the moment this is just an exploratory sketch but with serious intent. Local councils are being encouraged to make space available for self build houses and after a bit of polishing this design might gain some followers. Value for money would be very good if the drawings were all available and various trades all lined up and ready to make the next one. Practice makes perfect.
What next? Comments and criticisms would be good and then a list of the interested suppliers to put underneath here. If you are interested in owning one of these just let me know on the form and I’ll let you know how it develops.

Suppliers please step up:
Architects to draw it all up and polish the detail
Builders who like ICFs and SIPs
SIPs supplier (note the curvy roof)
Curved trim supplier – polystyrene.
Engineer for raising table and gliding sofa
TV partition wall
ASHP supplier
Solar pod for ASHP
Panels and micro-inverters
Power router
Panels – I’m set to import these.
Heat banks and energy design – that’s me.

Air Source Heat Pumps and the Renewable Heat Incentive.

The Energy Saving Trust heat pump survey in 2009 found that many users were not impressed at all. The follow up in 2013 improved the results but the final average system COPs of 2.45 (air source) and 2.82 (ground source) were still way below the headline figures quoted for these machines which are going over 4 these days.
What is really good about heat pumps is that they can deliver more energy than they consume in electricity.

The power multiplier

The power multiplier


So a small one would be just like this diagram; working on the power of an electric kettle but delivering the power of 3 to your hot tank – a COP (Coefficient Of Performance) of 3 then. By contrast your immersion heater delivers and also consumes the power of an electric kettle so it has a COP of 1.

Heat pumps are all sold with an industry standardised COP. This is misleading to say the least and the reason why optimism is defeated by experience. Far from being a fixed figure the COP actually swings widely depending on outside air temperature and temperature delivered in the home. The COP plots here show how a kick is engineered to give a good headline figure; that kink in the graph is exactly at the publication point.

A sneaky kink

A sneaky kink


You might buy a machine with a quoted COP of say 3.75 but while making domestic hot water on a cold night it will be working at less than 2. There are benign swings however and given a sunny winter day with some warm air to chew on an ASHP can see COPs almost up to 5.

Gas per kW.hr costs almost exactly a third of electrical power so after adjusting for efficiency a gas boiler is similar to a heat pump with a COP of 3. Many people in the survey would be comparing their new heat pump to a gas boiler; a formidable opponent when running on cheap gas. A gas boiler is much more powerful than most heat pumps and delivers at usefully high temperatures so a heat pump must have an overall COP of over 3 to justify a hefty purchase price and compare favourably.
To be fair the Renewable Heat Incentives state that heat pumps are suited to people without access to town gas. So for them heat pumps are suitable but perhaps the performance could be lifted further?

To winkle out some ideas we’ll take daily temperature data for January in Guildford (http://www.wunderground.com/) and relate that to a COP matrix made from the published data from a modern ASHP (inverter drive scroll, r410a, delivering to under floor heating at 35 degrees).
We will be looking to lift the COP by running the ASHP at the warmest ambient temperatures possible.
A look at a January temperature trace shows:
There is usually a 5 degree swing between the mean night time temperatures and the daytime mean.
Night time temperatures are flatter and longer than the sharper daytime peak at 1-2pm.
The morning transition from lows to highs is halfway there by 10am.
Temperature rises coincide with sunrise, not surprisingly.

Relating the above to the COP matrix:
Running a 7hr shift from 10am gives an average COP of 3.86 – much better than gas.
The equivalent night time shift only gives a COP of 2.92 – but almost as good as gas.
If the pump has to make hotter water for radiators these day/night figures drop to 2.7 and 2.11 and for 55 degree hot water making 2.3 and 1.85– gas beats this hands down.
Storing daytime running means that delivery temperatures probably need to be around 50 degrees leading to an average COP of under 3 although bigger storage tanks improve this.
ASHPs can be smaller if they run continuously day and night on an average COP of 3.4 – still 13% better than gas.
Direct electrical heating is often used to boost hot water making (COP = 1) and this can lower the average COP. If we can avoid this practice and run predominantly in the daytime it should theoretically be possible to get a COP of 3.35 (7hrs day, 2hrs night, 2hrs hot water).
Transmission: Put 100W/square metre through your floors and your feet will be uncomfortably hot so somewhere near half that will be a good yardstick for calculating the power you need to heat the floors then leave some surplus to top up a tank.

Conclusions
A small ASHP can run considerably more efficiently than a gas boiler in a modest well insulated house. Fan-coil units in bedrooms and underfloor heating elsewhere are essential. The heat pump should run in daylight except maybe for a boost before dawn to guarantee morning showers and take the chill off the floors.
I should just mention one little thing in favour of the heat pump; the RHI incentive of 7.3p/kW.hr pitched to pay for the heat pump itself after 7 years. You’ll need to spend another £4,000 on proper tanks to integrate any other sources such as a wood burning stove and a combination like that would be a joy for anyone living out in the middle of the country.

Of course if you make your own electricity, or you want to be green, then a heat pump is already the answer.

Heating News – Spring 2014

Heating News SPRING 2014
In this issue:
Heating Seminar – 28th May
500 litre heat bank – SPECIAL OFFER
Electricity bills audit
Back issues – on http://www.originaltwist.com
Stuff for sale

Heating Seminar – 28th MayFor anyone contemplating a heating project this will be a useful day spent discussing just about everything you need to know including:

Traditional heating – why it is out of date
How to evaluate your needs
Design your system on the PC
Accounting for seasonal demands – system alignment
Balancing and integrating a variety of inputs
Why heat banks are so good
Solar thermal and photovoltaic
Wood as a power source
Heat pumps a new era
Pool pumping on 200W

A great day out with lunch and a chat about your projects from 9am to 4pm. €90.
For delegates flying in the nearest airport is Perugia and accommodation can be arranged.
To reserve a place email me or use the contact form on the other page of this site or call 0039 (0)75 782 1816

500 litre heat bank – SPECIAL OFFER £4,100 including delivery to Central Italy worth £360. (Factory price for tank as specified here is £4,029)
There are many of these fitted in Umbria now and they all work a treat. This stainless steel Xcel heat bank from Specflue (they took over DPS) is still the easiest way to install a turnkey heating system that will run straight out of the box and integrate all your heat sources. The specification has been refined over the years and is now known as ‘The Italian Job’. All the pumps and controls are fitted and wired leaving just a days work to connect a few pipes. There is so much time and labour saved that this could be not just your best option but also the least expensive one too.

Specification
500 litre stainless steel tank (Telford) with 3 bar rating
35l/min plate heat exchanger for domestic hot water
Extra large 1” ports for gravity circulating stove.
Temperature regulation for a condensing boiler + thermostat
Class-A circulation pump for heating
Class-A pump and temperature control for underfloor heating
3kW immersion heater with Grasslin booster/timer
Over heat thermostat
Solar coil with sensor pocket.

You might notice some upgrades over the previous Italian Job. The tank is bigger and the pumps are the much more expensive A rated ones. The plate heat exchanger has been down graded to 35l/min. This is like 2+ combi boilers running at once but with less tank depletion than the previous 45l/min version. The latter is still available if needed.

Clearview 750 wood burning stove £2,200
Including gloves, temperature guage, colour of choice and UK delivery to the shippers. Free delivery to Italy with a tank order.This lovely stove has been so successful in many installations that I’d countenance nothing less. For most houses this will provide heating, hot water and even cooking without any additional heat sources. The best thing with this stove is the stainless clip-in back boiler which can easily be replaced if needs be. A stove with an integrated cast iron boiler usually means the whole stove has to be replaced – penny wise pound foolish!

Electricity bills audit
A fascinating exercise every time. Give me a stack of your last electricity bills and I’ll crunch the data into a table and graph to reveal all the interesting details along with some ideas for money saving changes. Your background consumption will be compared with the norm to show whether those bills are reasonable (as if) and that you are being charged fairly. An explanation of the Enel bill is part of the survey pack.
Surveys from €50. Report in print or pdf.

Back issues – on http://www.originaltwist.com
A selection of ‘heating News’ back issues can be found at the bottom of the blogs list to your right. The Heatingitaly web site has been superseded by http://www.originaltwist.com which gives more scope to discuss all sorts of interesting topics and to make the heating side less country specific.
The old site had a few useful spreadsheets for calculating various things to do with solar and heating in general. I can still send them out on request.

FOR SALE – ANYTHING
This is a market place for anything you want to sell not just heating related items.
One line per item please: as many items as you want
If you are a local send your list to my normal email title PATSMART
Petrol powered water pump as new €120 3313 404 008 Umbertide
Cast iron radiator, large – under half price €180 3313 404 008 Umbertide
Radiator, very small, white – under half price €20 3313 404 008 Umbertide
5 Blu-ray discs or DVDs with free Sharp Blu-ray player €50 3313 404 008 Umbertide
Toyota RAV4, 2007, 110,000km, chains, metallic black €10,000 3313 404 008 Umbertide
Restoration – lovely carved French bed, padded head board €100 075 782 1816 Umbertide
Childs bike 6 – 10 yrs knobbly tyres, good condition €40 075 782 1816 Umbertide