Air source heat pumps

Imagine creating energy out of thin air.

An Air Source Heat Pump is a unit that stands outside your home and is connected to your heating system. In a well insulated home, it can take the place of a central heating boiler.

Air Source heat pumps extract heat from the outside air. They are effective all year round (even at temperatures as low as -15°C) and in a well insulated home they can take the place of a central heating boiler. For residential heating systems they are at their most effective when used for lower temperature applications such as underfloor heating, but they can be configured to cope with heating most houses, whatever the age and type of property.

Air Source Heat Pumps are an eco-friendly and cheaper alternative to oil and are often installed in new build properties in areas where there is no mains gas. Properties that have an existing oil-fired boiler can benefit from the addition of an Air Source Heat Pump, as they can be easily incorporated into the heating system to improve efficiency and reduce running costs. High output, commercial air source heat pumps are also available. Air source heating systems, with multiple units linked together, can be designed for large scale installations, as an alternative to a ground source system, where groundwork is not practical.

Because air source units do not require any groundwork, installation is quick, easy and very cost-effective.

Benefits

The main benefits of Air and Ground Source Heat Pumps can be summarised as follows:

• They save money. An Air or Ground Source Heat Pump can help to achieve significant fuel cost savings compared to direct electric heating systems (e.g. storage heating), gas boilers, oil boilers and some renewable energy systems, such as biomass boilers. Additionally, the Government has introduced the Renewable Heat Incentive for owners of heat pumps. Commercial building owners will benefit from a subsidy from September 2011 and residential building owners from October 2012 (tbc). This subsidy will significantly shorten the ‘pay-back’ time, making a heat pump an even more attractive option, producing a return of about 12% on the initial investment.
• They are an eco-friendly alternative to oil, gas and LPG. Although they require electricity to operate, the output generated is around 2.9 to 4.0 times the power input (known as the CoP or Co-efficient of Performance). If a renewable source of electricity is used, for example, photovoltaic panels, they are completely carbon neutral – and you would then not only benefit from the tariff payment for the heat pump, you would also benefit from the new Feed-in Tariff scheme on the PV panels.
  • To secure the Renewable Heat Incentive you must have a heating COP > 2.9
  • Geothermal International designed systems are expected to achieve COP’s as follows:
    • Heating only up to 3.8
    • Heating and Cooling system – Heating only up to 4.8
    • Heating and Cooling system – Cooling only up to 5.8
• They don’t require any fuel storage space, unlike oil and LPG which require large storage tanks, and biomass boilers which require wood/pellet storage. There is also the peace of mind that there is no need to store large volumes of combustible fuel on the premises. They do not require flueing as there are no harmful emissions.
• Low maintenance. The basic mechanism is similar to a refrigerator, with few moving parts and few things that can go wrong – all you need to do is keep the unit clear of leaves and debris. The most costly part in the unit is the compressor and you have the option to extend your warranty if you would like the reassurance that all parts and labour are covered in the longer term.

How They Work

Heat Pumps operate in a similar way to a refrigerator – but in reverse. Heating and cooling are achieved by moving a refrigerant through various indoor and outdoor coils and components. A compressor, condenser, expansion valve and evaporator are used to change the state of refrigerant from a liquid to hot gas and from a gas to cold liquid.

The main stages of the process are as follows:

• Liquid refrigerant passes through the outdoor evaporator coils at a low temperature.
• Air is drawn in to the unit and the temperature of the outside air causes the refrigerant to boil and become vapour.
• The vapour is drawn into the compressor, where the temperature of the vapour is increased to over 100 degrees.
• The vapour then enters the condenser heat exchanger and heat from the vapour is transferred across the coils. As the vapour cools it condenses back to a liquid, which releases considerable latent heat to the air passing over the heat exchanger.
• The refrigerant, which is now a very cold liquid at high pressure, passes through an expansion valve, which reduces the pressure so that the cold liquid can re-enter the evaporator and begin the cycle again.

At stage 4, the heat is transferred to the domestic hot water tank and to an underfloor system and/or central heating radiators.

System Design

The key to achieving optimum levels of performance and efficiency lies in the design of the heat pump system. From small units for individual dwellings to large scale commercial installations, we have the expertise to design the best system to fit the building type, the budget and the heating and cooling requirements.

Feasibility Study & Discussion Document

Our design service begins with an initial feasibility study. We will ask you for an outline of the heating and cooling needs, along with details of the building layout, plant room etc, if applicable. A member of our technical team will prepare a discussion document, with outline installation costs, estimated carbon run costs and estimated savings.

Site Visit

This provides the opportunity to discuss the project in detail and for the engineer to gain a full understanding of the client’s requirements.

System Design

Using specialist software, our technical team will produce a detailed design document, which includes recommended siting of equipment, plant room layouts and interfaces with internal heating distribution. Once the system has been designed and approved we can hand over the drawings to your approved installer or we can undertake the full installation process. Geothermal International will be responsible for commissioning the system.

After Sales Service

Our fully trained maintenance and service engineers cover the whole of the UK and provide our customers with expert on-site supervision, technical diagnostics, repair services and planned maintenance capability. Field technicians, field engineers and in-house engineering support teams work closely with our clients to develop specific solutions for individual projects. Our aim is to provide our customers with the quality service and support required for maintaining high reliability and long term use of their equipment. Our services include:

• Repairs
• Bespoke service agreements
• Spare parts packages
• Equipment upgrades
• Control Software
• Supervisory Management Systems

Product Warranties

Geothermal International offers a wide range of warranty & maintenance options. Our standard warranty is for 2 years parts & labour, from the date of supply. At the end of this period, extended warranties are available, to ensure peace of mind over the lifetime of the product.

Heat pumps use similar technology to a refrigerator, so servicing and maintenance needs are minimal. However, low level maintenance to check electrical connections, clean filters, check fuses etc is recommended, to ensure that the appliance runs without problems for many years. Annual servicing and operational checks can be built into extended warranty agreements. Extended warranties also cover the equipment in case of failure of a major component, such as the compressor.

An extended 2 year warranty package typically includes:

• Annual service checks to ensure the appliance continues to function correctly & efficiently
• Annual parts & labour cover, in the event of any breakdown due to mechanical or electrical failure of any component in the appliance (not caused by damage, incorrect use or application of the appliance and as long as it has been continually maintained by us)

Bespoke maintenance and warranty packages can also be arranged.

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For more information on the Renewable Heat incentive please see these RHI FAQs.

Want to know more? Contact us using our form or call our Bristol office on 08456 718441.