How do absorption heat pumps work

The diagram below demonstrates the process. The strong ammonia vapour is forced into the Condenser 2. Whilst the weak ammonia solution is circulated into the Absorber 5 via an expansion valve which maintains pressure differential.

Because the vapour has changed state and become a liquid it effectively gives up its latent heat of vapourisation into the heating media e. The liquid now proceeds to the Expansion Valve 3. The commercial boilers would operate in the event that the thermal load exceeds the heat pump output.

Alternatively the heat pumps could be sized for the lower grade heat loads underfloor heating and hot water pre-heat with the commercial boilers serving the higher temperature radiator circuits or main hot water calorifier. An example application of a gas absorption heat pump supplying heating and domestic hot water is shown in Figure 4. Gas-absorption heat pumps deliver a high level of fuel efficiency during operation, compared to traditional heating boiler plant, if used with lower load temperatures of around 35C.

Higher efficiencies can still be achieved at load temperatures of up to 50C. During operation, the refrigerant cycle uses natural gas or LPG or, potentially, biogas assisted by the energy in the air, rather than electricity to provide heat. Ongoing heatpump operating costs are also lower. The starting current of a gas absorption heat pump is considerably lower compared with more conventional ground and airsource heat pumps, reducing the reliance on local electricity supply infrastructure.

There is no compressor used within the refrigeration cycle — the solution pump see Figure 1 used within the system to raise the solution pressure only consumes a small quantity of electricity; for example, for a 41kW gas-absorption heat pump, the electricity requirements for the solution pump is only around 1. Overall gas-absorption heat pump performance is measured in efficiency terms, and not simply the traditional coefficient of performance COP.

Table 1 outlines the performance of an example unit when used with different ambient air temperatures and water flow temperatures. The cooling and heating is accomplished by this circulation. As the basic principle of operation is the same as an electric vapor compression heat pump, the primary advantage of an engine-driven heat pump is the operating cost. How Absorption Heat Pumps Work. How to reach us. Newsletter subscription.

Follow us:. Condensation : refrigerant flowing from the compressor passes from a gaseous to liquid state, giving off heat to the outside. Condensation : refrigerant flowing from the generator passes from a gaseous to liquid state, giving off heat to the external fluid water or air.

Expansion : passing through the expansion valve, the liquid refrigerant cools and is partially transformed into vapour.