What is a heat pump?

A heat pump is essentially a refrigerator working in reverse. Simply put, the air we all breathe inside buildings and outside can chill a room which provides hot water as a by product or use the air outside to provide space heating and hot water. In operation it draws air into one side of the heat pump and dumps out the other side the air at a reduced temperature.

In the UK a ducted air to water heat pump was  located in the loft space of a domestic home, (can also be installed in a garage or high up in roof of a commercial building where waste heat can be recycled back into hot water for office space heating and hot water. Where no indoor space is available an external range of heat pumps are recommended which have the ability to work at an ambient air temperatures below -10c. The ideal air temperature is 10-15c to achieve the maximum COP (coefficient performance) of 3-4. In hot climates of the world where expensive air conditioning is used, this could also cool areas of buildings down as long as there was a constant  hot water demand need as a by product.

What will they do for me?

The range of heat pumps that we can supply with take heat out of the air and convert it to hot water through a plate heat exchanger after being passed through the compressor, to be used as hot water for showers/swimming pools & space heating. Heat pumps are particularly effective when combined with solar thermal collectors. With these two technologies combined, along with an energy efficient thermal storage system, the gas/oil boiler is redundant in new homes where there is no gas mains.

Where will it go?

An ideal location for a ducted  heat pump is in your roof space of a building, as long as the cold air can be ducted away. There is usually a large amount of ‘wasted’ heat to be found there. The added benefit of transferring heat out of the loft and into your hot water tank is that it cools your loft space, reducing the ‘stuffiness’ of the building. Alternatively the heat pump could go outside in the garage or in commercial buildings, plant rooms and commercial kitchens.

When its cold, will it still work?

The remarkable thing about heat pumps is that they can extract heat from incredibly low temperature. It would not be unusual for your heat pump to continue to work in temperatures as low as -15°C, except in these days of global warming, the internal roof temperatures and inside garages outside of any wind chill rarely fall below -5c even if freezing outside.

How effective is a heat pump?

For every unit of electricity used to run the heat pump, the heat pump will give you between 3 -4 units of heat back in return. The ratio of energy in to energy out is called the ‘co-efficient of performance’ (COP). The higher the COP the more effective the heat pump is at transferring heat to the place where you want it. To put this in context, a traditional gas boiler has a COP of around 0.65, compared with a heat pump of around 3. This makes the heat pump over four times as effective at generating heat as a traditional gas boiler.

Why haven’t I heard of one before?

Heat pumps have been available for many yeas, but new compressor and refrigerant gas technology recently introduced into the marketplace has dramatically increased efficiency levels, thus making it a financially rewarding technology across many sectors.

Will it need any maintenance?

Heat pumps are incredibly reliable and are automatically controlled, so you won’t have to call a heating engineer out or fiddle with anything. Look at a heat pump as you would your deep freeze of refrigerator, it runs 24 hrs a day off and on, week in week out and year after year.

Won’t it be noisy?

Our range of heat pumps run incredibly quietly, just like a refrigerator  and freezer – you wouldn’t even know they were there as they are mainly running when most people are up or at work. In the evening with the TV on, people talking and mainly located downstairs.

How efficient are your heat pumps?

Our heat pumps are designed to operate with a COP of between 3 and 5, offering you one of the best energy values in providing hot water and heat to where it’s needed the most and 24/7 affordably.

What about ground source heat pumps?

The air to water heat pumps that we supply are the cost effective alternative to ground source heat pumps. A ground source heat pump system involves digging up large areas of you garden, drilling a deep hole or trench to lay down hundreds of meters of pipe, all at great expense. The belief by those who do not fully understand this technology is that the temperature 2-3 meters below the ground surface has a stable temperature of around 15c, if this were the case, why is our cold water in the 6 months of winter arriving at the kitchen tap at around 6c? Another issue is the degrading of the ground temperature.

A typical cost including installation is around £15,000 – £20,000.

Our air to water heat pumps essentially work on the same principle, but without needing to do any of the above. Why take heat out of the ground when it’s easier, cheaper and more effective to take it out of the air and cost 70% less?

Another problem with ground source heat pumps is how long will it be, after extracting heat from the ground before the temperature remains colder, given the limited summer season to replace the heat drawn out over a period of 8 months.

The key difference between the two types of air to water heat pumps, is that one type is designed to be situated outside, big use for heating swimming pools in warm climates, the other type is for internal use, like the attics/lofts of homes and buildings, garages, commercial warehouses and buildings with high roofs where heat gets trapped.

The combination of air to water heat pumps and solar thermal collectors

In 2005, Powertech Solar Ltd started to combine  hot water generated from an air to water heat pump with the hot water generated by our Apricus vacuum tube heat pipe collector.

Having already designed and fully developed the Powertech Multi Fuel thermal store to operate for both heating and hot water at mains pressure at 65c, followed by the establishment of the Ply Pipe under floor heating system in the market, it now seemed the right time to offer an alternative to the conventional gas/oil boiler central heating system.

What held back this Hybrid alternative was the higher temperature (up to 80 C) which all thermal stores need in order to meet both the space heating load and that of hot water at mains pressure at the same time, across the winter months.

Like all Combi boilers which also suffer from lower temperature and flow rates during 6 months of winter when the incoming cold mains drops to around 6c, all thermal stores suffer much the same problem.

At Powertech we identified the problem, made a few design changes, sadly increased the cost to achieve the 60c temperature our Multi Fuel thermal store operates at, but allowed us to meet this temperature of 60c through the 2 sizes of air to water heat pumps we now offer along side our high efficiency Apricus collectors, with the back up of a 6 and 3 kW immersion heaters.

If a gas boiler gives you a further energy option in order not to be 100% reliant on electricity, we recommend a much smaller boiler.

Do keep in mind, if you have no electricity, you still cannot run your boiler as its needs power to the pump and programmer/controller.

Let us know, as we have a 600 watt UPS system which backs up the boilers electricity needs during power cuts.

What ever your ideas, requirements for a sustainable renewable energy/water future, we have 99% of the answers and the products to create your bespoke design, which we guarantee will work for you at the most cost effective way.