What types of renewable energy heat pumps are there?
Heat pumps can use a range of heat sources and operate through a wide range of temperatures from 40°C up to 130°C. They can be used in many applications and make use of any suitable heat sources that are available. Heat pumps can be categorised into four key types: air source; ground source; water source; and high temperature – for use in industry.
There are four main types of heat pump
- Air source heat pump
- Air to air : produces warm air which is circulated by ventillation units to heat your home; also for cooling in warmer weather.
- Air to water :distributes heat via radiators or underfloor heating and also heats your hot water
- Ground source heat pump
Requires pipes to be buried in the garden to extract heat from the ground to heat radiators, underfloor or warm air heating systems and your hot water.
- Water source heat pump
An alternative to a ground source system extracts heat stored in water or a lake
- High temperature heat pump
These are used in industry for high grade, high carbon intensity heat processes, such as drying, pre-heating and distillation. A waste heat interface recovers heat from site processes or CHP plant and supplies it to the heat pump, which then upgrades the heat to a higher temperature. This can be used in processes, to generate low pressure steam, or provide high temperature hot water.
Air to Water Heat Pumps
Most of the heat pumps installed in the UK are air to water heat pumps, which provide both space and water heating. They can be installed on almost all properties, including flats. A normal pump is about the size of a fridge, and you just need a place outside where it can be fitted to a wall or placed on the ground, with space around it to get a good flow of air.
All air source heat pumps do produce some noise, as they contain a fan, but the modern ones are much quieter which is rarely a problem.Air-to-water heat pumps are simple to install and require little maintenance..They are an economical replacement to oil fired, coal and electric central heating, and a boon if you don’t have mains gas. And, as you won’t need a boiler, it frees up space in the home too. (Although electricity is needed to power the pump, extracting the heat from the outside air, a limitless renewable resource, even in temperatures as low as -18°C, far outweighs the cost of the electricity.)
Image right demonstrates an air-to-water air source heat pump
(Image via Home Heating Guide)
Air to Air Heat Pumps
Air to air heat pumps are essentially air conditioners that work in reverse. The biggest benefit is that they have the ability to keep you nice and cool in the hot summer months and warm and toasty during the long cold winter.
It pumps heated air into your house, therefore, you need another mechanism to heat your water. This is essentially seen as a hybrid system - which is a heat pump and traditional boiler combined. The concept being that the heat pump does most of the work, but falls back on the boiler to help out in particularly cold weather, when the heat pump may struggle.
However an air to air heap pump hybrid does have some advantages. The pumps are cheaper and have a good efficiency. Since they don’t use radiators, you won’t need to install bigger ones, although you may need ducting (pipes) in order to carry the hot air around to different rooms.
Another big benefits of an an air to air air source heat pump is their energy efficiency. These systems use electricity to move heat from the air outside to the air inside, rather than generating heat through the use
of fossil fuels. This means that they can provide heating and cooling at a much lower cost compared to traditional systems.
In addition to being energy efficient, air-to-air heat pump systems are also very cost effective to install. They do not require the installation of any additional fuel lines or tanks, as they solely rely on electricity to operate. This makes them a good choice for homes that do not have access to natural gas or bottled gas.
Image left demonstrates an air-to-air source heat pump
(Image via Home Heating Guide)
Ground Source Heat Pumps
Ground source heat pumps are the most energy efficient but, due to the cost and complexity of installation, are better suited to new builds during the later construction phases
Ground source heat pumps (GSHPs) use pipes that are buried underground to extract heat from the ground, which is then used to heat radiators, underfloor or warm air heating systems and hot water in your home.
A ground source heat pump circulates a mixture of water and antifreeze around a loop of pipe, called a ground loop, which is buried in your garden. Heat from the ground is absorbed into the fluid and then passes through a heat exchanger into the heat pump. As the ground stays at a fairly constant temperature under the surface, the heat pump can be used throughout the year.
The length of the ground loop depends on the size of your home and the amount of heat you need. Longer loops can draw more heat from the ground, but need more space to be buried in. If space is limited, a vertical borehole can be drilled instead.
More details can be found on the Ground Source Heat Pump Association website.
Water Source Heat Pumps
A water source or lake heat pump effectively works in the same way as a ground source heat pump. By using heat stored in the lake water and lake bed. The collector circuit is laid on the bottom of the waterway and carries heat to a waterside home. Using heat from water reduces energy consumption in an efficient way.
- Air source heat pump
