Solahart Atmos Heat Pump Water Heater delivers hot water by efficiently utilising a free and abundant source of energy - the heat that is locked in the air around us. Even on a relatively cold day, the air has some heat which is available to be transferred to a fluid. The secret is to make the fluid even colder than the air. You can see in the diagram at step 1, that liquid refrigerant begins at high pressure before being forced through an expansion valve (2). This sudden release of pressure cools the liquid to allow it to absorb heat from the surrounding air. This valve is designed to carefully regulate how much refrigerant passes through it.

On cold days, less refrigerant passes through; the smaller amount of fluid expands faster into the available space and cools to a lower temperature. On warmer days, more refrigerant is allowed to pass through - it doesn't need to cool down as much because the air has more available heat to transfer. As the cooled refrigerant passes up the coiled tubes, air is blown over the tubes to warm the refrigerant till it becomes a vapour (3). To make the heat pump more efficient, part of the air is actually drawn from around the motor. This helps cool the motor as well as reclaiming potentially wasted heat.

Next, the low pressure vapour needs to be compressed again to return it to its original pressure (4). The temperature has by now reached around 80ºC. From here the refrigerant is pumped to the heat exchanger where it passes down a series of narrow tubes (5). The cold water is pumped up an alternating set of tubes to allow it to absorb the heat. Each time water passes through the heat exchanger it emerges around 10-15ºC hotter. When all the water in the attached storage tank reaches its pre-set temperature, the heat pump switches itself off.