Grant Aerona R290 heat pumps use an air to water system which uses energy absorbed from the air and transfers it to a water based heating system. The process uses the same vapor/compression cycle that extracts heat in a domestic fridge. A refrigerant with a low boiling point is exposed to external air temperatures in an evaporator. The liquid boils off to a gas and absorbs the thermal energy of the air. This gas is then compressed, increasing the heat energy contained within the refrigerant. It then passes through a heat exchanger where it condenses back to a liquid form, whilst transferring the heat to the water of the heating system. The liquid refrigerant is then re-circulated through the evaporator and the cycle is repeated.
When considering your hot water requirements as part of your air source heat pump system, the time selection and programming set up by you and your installer will require a slightly different approach to that of a conventional gas or oil boiler. This is because an air source heat pump is not designed to supply space heating and hot water at the same time.
Using heating controls
The heating controls installed by your engineer alongside your heat pump will communicate with your heat pump to manage the space heating and domestic hot water production. Typically, these controls will involve a simple two-channel programmer that controls when your heat pump is working to provide space heating and when it is working to heat your hot water.
Some control systems will have a hot water priority control where the operation of the heat pump is automatically switched to heat hot water when required (for example when you turn on a hot water tap) and then returning automatically back to heating when the demand for hot water stops. If you are unsure about the type of controls set up with your system, please speak to your installer.
Hot water priority explained
When a domestic hot water (DHW) heating period is requested, your Grant heat pump will give priority to hot water production and temporarily deactivate the central heating. To reduce the time the central heating is inactive and to maximise central heating recovery, it is recommended that individual DHW timings are limited to short periods of no more than one hour. It is also recommended that these DHW periods should be limited to three or four times a day. Furthermore, if your installer programmes the DHW heating times to come on in the early morning and late evening, this will further enhance hot water recovery times while also ensuring the space heating temperature is maintained throughout the day. The infographic below helps explain this further.
Using the Aerona Smart Controller, installers can set, view and adjust the time schedules for the heating circuits, domestic hot water and the heat pump’s on/off schedule as well as accessing in-built system configurator features which support the set-up and commissioning of an Aerona R290 heat pump and the system circuits. Supplied with the Aerona WiFi Hub, the Aerona Smart Controller can also be accessed remotely by homeowners and installers using a supporting browser-based platform and app. Homeowners will be provided with in-depth instructions on how to operate their Aerona Smart Controls when their air source heat pump is being commissioned by the Grant team.
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