Cheap PV panels have radically changed a few of our preconceptions about heating. The heating system layout has become much simpler (and less expensive) as under-floor heating and wet solar panels are deleted and heat pump connections are simplified.

heat pump – heating and cooling

The heat pump connections are easier thanks to the Original Twist Hybrid Heat Pump which indirectly supplies chilled water without breaking the rules for the RHI incentives. Note that the system copes with 2 set points from the heat pump; hot water is routed to the hot tank while the heating is kept going with stored energy from the cooler tank. For the lower set point, heat is sent directly to the cooler heating side without disrupting the stratification in the hotter tank. The system can heat either tank while simultaneously supplying chilled air – how cool is that? An extra immersion heater helps use all that extra PV energy and for absolute perfection I’d have an external one – e.g. the Willis (no short cycling and easier to service and delivers heat to the top of the tank).

The cool tank has a large coil to preheat the DHW going to the hot tank heat exchanger and now there is a large choice of suitable tanks thanks to the heat pump drive. 3sqm of coil surface is common.

You can see the original system here along with a long list of all the benefits which still make this the best system on the planet.

You might have sussed that with 2 tanks here and another from the heat pump system your tech room is going to be large and, dare I say, impressive. I imagine all the tanks raised slightly on a low wall with wooden slats across the top. This allows most of the pipes to be hidden. The tanks are often raised when a wood burning stove is connected and gravity circulation is required.

What’s the point? Well it’s all about integration of multiple input sources, like a wood burning stove or a gas boiler along with a heat pump. Many experts say you can’t integrate all these things but they are wrong.

There is a commonly recurring problem with heat pumps and that is that existing pipework is too small to deliver much more than 6-10kW. The solution, of course, is to stick with the low powered heat pump and add a mini-split air to air heat pump.They are cheap, independent of any existing systems and they do aircon. This immediately ducks all the attendant problems with transmission and low power and makes the whole set up even simpler.

With a mini-split on board you might go really simple and have just one heat bank, a wet connected stove, a gas boiler (get one while you can) and no other heat pumps. All very simple and enough money saved to buy some PV panels.

….. and don’t forget the Original Twist fan-coil units – too good to miss.