How DOES A HEAT PUMP WORK?
How does a heat pump work?
A heat pump extracts heat from the air outside using electricity. This means you get a bigger quantity of heat with less electrical power usage.
Air-source heat pumps give you comfortable, consistent heating and hot water, with the added benefit of:
- Less energy: Heat pumps use 4x less energy than even the most efficient boilers to generate the same amount of heat.
- Less carbon: That efficiency means you’ll instantly slash your heat carbon footprint by around 70%. Plus, they run on electricity, which gets greener every year.
- Less maintenance: A heat pump can last 20 years – about twice as long as a boiler – and needs less pricey maintenance.
TRIED AND TESTED
A heat pump uses similar natural physics concepts as a fridge, using a heat exchanger. Our heat pump works bidirectionally so it could even be used as a fridge, although it’s better applied to keep your home cool in summer.
Developments in the efficiency of refrigerants, evaporators, and the other components in the heat pump mean they now produce heat very efficiently, and subsequently are far greener than traditional heating methods.
The heat pump works by extracting thermal energy from the air, and using convection, generate heating and hot water for your home. By harnessing the natural thermal energy in the atmosphere heat pumps can produce more than 4x the amount of energy that is put into them. Our 6kW heat pump has an SCOP of 4.9. This means for every 1kWh of energy used, the pump produces 4.9kWh of heating energy for your home.
Gas Boiler COMPARISON
We use the analogy of the tortoise and the hare to visualise the difference between the two forms of heating.
A gas boiler works fast, with high energy output to heat up water, whereas a heat pump works slow and steady holding the temperature at a more consistent level.
We also like to claim, as the tortoise, the heat pump wins the race.
Traditional boilers tend to be oversized compared to heat pumps in terms of capacity.
As a general rule a house that requires 5kW of energy would tend to have a 30kW boiler installed.
This is because combi boilers are designed to be reactive, providing heating on demand. In this case, your thermostat will monitor your room temperature and turn the system ON and OFF to meet the desired room temperature. This creates a yo-yo affect between desired temperature and actual, and also between your inflow water temperature and your design flow temperature of your system (~35°C for underfloor heating and 45~80°C for radiators).
This greater temperature rise in this scenario requires more power.
Heat pumps heat your water much more gently, over a longer period of time, and keep a constant flow.
Having heat pumps with a 30kW capacity requires an expensive unit, and usually 3-phase power to achieve. As a result, heat pumps are designed more carefully to facilitate lower capacity.
Heat pumps keep water flowing and by maintaining constant temperature in the system, there is rarely a need for a large surge in power to combat dropping room temperatures. The heat pump works to keep the water inflow temperature within a couple of degrees of your design flow temperature, rather than 5~10 degrees, as can be the case in a boiler system.
Adlår heat pumps are installed with extra capacity built in, and in combination with temperature sensors and pre-programmed environmental heating curves, we can account for the worst case scenarios (when outside temperature drops below -10°C, and the hot water temperature isn’t keeping up with your thermostat demanded temperature).
Our extra capacity includes:
- 3kW Immersion heater, within a 60 or 90 litre buffer tank
- 1.5kW domestic hot water (DHW) cylinder air source heat pump (ASHP)
The buffer tank smooths out demand, having heating hot water available to distribute to your heating system. The 3kW immersion heater can be activated if the heat pump’s capacity is close to maximum and the temperature settings aren’t being met by the heat pump alone.
The 1.5kW DHW ASHP cylinder works independently from the heating, to supply only for your domestic hot water. As DHW takes priority over room heating in most systems, by splitting the system as we do, we avoid the heat pump being in over capacity and prevents heating capacity for hot water from ever being diverted to the DHW.
MISCONCEPTIONS
These days heat pumps can actually heat water up to these higher temperatures.
The question is, why would you want to? Heat pumps work more efficiently at lower temperatures and with modern low temperature radiators you just don’t need to heat your water up to 60 degrees, or higher.
By running your radiators slightly longer at a lower temperature you save money, have less heat loss in your radiators, and have a more pleasant living environment.
As above, the feeling of constant low heat is much nicer than yo-yoing of heat you receive with a boiler going on and off in spikes and troughs.
It is also a nice feeling to see your energy bill go down!
Air source heat pumps can actually work in temperatures as low as -20 °C when properly installed. Norway, Sweden, and Finland have the highest heat pump adoption rates in Europe, and are equally some of the coldest countries.
When it gets very cold, the heat pump will need to use a bit more energy than usual to keep your home cosy, but as our heat pump is designed for Swedish winters, the UK’s milder climate means our heat pump has no problem keeping up.
Our heat pumps are also installed with outdoor temperature sensors and climate control systems, which can engage immersion heaters to boost hot water if in the rare case the heat pump isn’t efficiently getting your hot water up to the design flow temperature.
Heat pumps are smart. They use outside temperatures to control your heating curves and with your input they can learn your usage and active times in the house to ensure that slow and steady heat is produced so when you walk in your home the temperature is perfect.
Then it works slow and steady in low eco modes to maintain that temperature.
You don’t need to worry about going to the thermostat and hitting boost.
GETTING TECHNICAL
Heat pumps operate using two circuits. The first is the water system, which contains your hot water, and the second containing a refrigerant. Possible refrigerants include R410 or CO2 (R744), but increasingly propane (R290) or difluoromethane (R32) is used to achieve better efficiencies. Our heat pumps are equipped with R32.
Air from outside is moved over the heat exchanger by a fan, causing the refrigerant to evaporate into a gas.
The refrigerant is then compressed, increasing the temperate to be able to heat your water sufficiently.
The heat in the refrigerant gas is is then transferred to the hot water in the heating system at an exchanger.
The generated heat will move through the home (via underfloor heating or compatible radiators).
The now-liquid refrigerant will decrease in temperature by passing through an expansion valve. Restarting the cycle.
Heating Mode:
COoling MODE:
Learn MORE:
1 Evaporator
2 4-Way Value
3 Fan
4 Compressor
5 Expansion
6 Heat Exchange