Advice Notes on Ground & Air Source Heat Pumps Technology Economics for the NPA Region

GSHP

The Advice Notes aim to provide introductory material for entrepreneurs, startups and SME’s, considering to enter into the renewable energy sphere and based in the NPA regions partners to GREBE. The scope of the Advice Note covers regional, trade and industry, renewable energy (RE), technology information from Ireland, Northern Ireland, Scotland, Iceland and Finland. Different partner regions have different level of deployment of the various RE technologies covered by the Advice Notes. Thus, the level of information will vary depending on the level of deployment for each technology. For example, wind is not deployed on a large scale in North Karelia (Finland); however, it is widely deployed in Scotland, Ireland and Northern Ireland.

Full details are available on the GREBE website:

http://grebeproject.eu/wp-content/uploads/2017/10/GREBE-Advice-Notes-GSHP-ASHP.pdf

The focus of the Advice Notes is on regional information of some of the main economic characteristics sited as imperative, when making an informed choice, regarding which RE technology may be the optimal choice for a new business venture:

  • Costs and economics associated with the relevant technology
  • Support schemes available, relevant to the technology
  • Government allowance/exemptions, relevant to the technology
  • Funding available for capital costs of the relevant technology
  • List of the relevant to the technology suppliers/developers, with focus on local/regional, suppliers/developers and the products and services they offer.

Geothermal Map

Heat pumps offer a means to access and utilize the thermal energy that is contained naturally in air, water or the ground. Heat pumps extract low-grade energy from the surrounding environment (air, water, and ground) and transform it into usable energy at a higher temperature suitable for space and water heating. Any kind of heat pump will need to be powered by electricity. Thus, the coefficient of performance (COP), which is the amount of electricity input, is a very important factor when considering GSHP or ASHP. For example if it takes 1 unit of electricity input to produce 4 units of heat output, the CoP will be 4. One of the crucial factors for the CoP is the temperature required by the heating system as CoP is higher when the required temperature is lower (35- 45°C).

Therefore, heat pumps are appropriate for buildings that have these lower temperature heating systems. As these can be costly to retrofit, new buildings which are already fitted with low temperature heating are apt for heat pump technology. For a GSHP or ASHP system a minimum of CoP 3 is needed in order to be a viable option offering savings both in costs and C02 emissions.

The Advice Notes will cover Ground Source Heat Pump (GSHP) and Air Source Heat Pump (ASHP).

GSHP systems make use of the temperature difference between above-ground (air) temperatures and below-ground temperatures for heating or cooling. GSHPs take low-level heat from solar energy stored in the earth and convert it to high-grade heat by using an electrically driven or gas-powered heat pump containing a heat exchanger. A fluid, mixture of water and antifreeze, is circulated in a closed loop system, which picks up heat from the ground and then passes through the heat exchanger in the heat pump, which extracts the heat from the fluid. Heat pumps deliver heat most efficiently at about 30°C which is usually used to deliver space heating to buildings. GSHPs cover a wide range of capacities, from a few kW to hundreds of kW.

Air-source heat pumps (ASHPs) work on the same principle as GSHP, by taking low-grade thermal energy from the air (using an air-source collector outside of the building) and converting it to useful heat by means of the vapour compression cycle. ASHPs are in common use in commercial-scale heating, ventilation and AC systems as they can meet both heating and cooling demand. Installation of an ASHP includes fixing an external unit and drilling holes through the building wall with and an extra pipework may be required. The main steps for deciding if an ASHP is an apt choice are the same as those for a GSHP system, without the need for a ground survey.

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