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More than 200 HVAC&R industry experts gathered at the 5th annual ATMOsphere Europe 2013 conference with the main theme being “Natural Refrigerants”-Solutions for Europe”.

View Danfoss Dream Solution for a supermarket concept case- Presentation from ATMOsphere Europe here.

ATMOsphere Europe 13 consisted of a series of interactive workshops bringing together decision makers from industry and government to change the future of natural refrigerants.  This presentation was delivered by Torben Funder-Kristensen, Head of Public Industry Affairs at Danfoss. The presentation focuses on a project recently implemented at a grocery store in Norway. One CO2 compressor takes care of all the temperature generation, both cold and warm. Utilising the heat from the refrigeration system rather than electricity, it also melts the snow around the store. Overall, the goal of the project is to obtain between 30% - 50% energy savings in the systems.

 

The Presentation covered:

  • The project and the facts about the case
  • A description of the store refrigeration & HVAC system build up
  • Why CO2
  • The controls used in the concept
  • Actual status
  • Conclusion and next steps

Conclusion:

  • An advanced energy integrated supermarket installation has been realised within the CREATIV project in Trondheim, Norway.
  • The energy sub -systems are interconnected and controlled to minimize the entire power consumption of the supermarket building.
  • Danfoss controllers manage & optimise:
    • Operation of the refrigeration system
    • Heat storage devices
    • Air Handling Unit
    • Heating systems
  • Besides being a show case for the Industry this system will be used to test and develop new advanced controls

Many case study sessions that focus on cutting-edge natural refrigerant technologies and projects in the areas of industrial, commercial and transport refrigeration as well as heat pumps and air-conditioning were included at the ATMOsphere Europe 2013 Conference.

The full range of presentations from ATMOsphere Europe can be found on www.ATMO.org.

ATMOsphere

 

Recovering waste heat produced by the refrigeration process can save energy and cut costs.

Industrial and commercial companies of all sizes and in all sectors use refrigeration plant to reduce the temperature of buildings.

The food industry also uses refrigeration in the production and storage of food and drink.  Heat recovery equipment can be fitted to existing plant, or companies can specify new plant with heat recovery already integrated. In both cases, the technology allows waste heat to be re-used for space heating or hot water.

The business case - The cost depends on size, but even on some small units, companies could recoup their investment in less than five years.

For a 200kW chiller, heat recovery equipment would cost around £10,000 installed. Assuming 3,000 hours’ operating a year and current gas prices, the heat recovered could add up to a saving of £5,400 – giving a payback in less than two years.  A new 150kW capacity chiller with full heat recovery would be around £26,000 installed, but operating on the same number of hours as above, could save £13,500 and give a payback in around two years.

How to implement heat recovery in refrigeration (CTL056) – Click to view

Further information on the Carbon Trust guidance documents click here.

BSRIA (the British Association for Chemical Specialities) has published a guide on Water Treatment for Closed Heating and Cooling Systems.

The new Water Treatment Guide called: Water Treatment for Closed Heating and Cooling Systems (BG 50/2013) provides an introduction to current theory and practice of water treatment in closed building systems.

The guide is aimed at design engineers, installing contractors and the maintenance staff who are responsible to looking after the completed systems; it also provides guidance for facilities managers and those who are tasked with choosing the most appropriate water treatment programme for their systems.

The main objectives of a water treatment programme are to efficiently maintain the systems alongside achieving cleanliness and prolonging the system life, this guide therefore explains how to achieve this through:

  • system design
  • installation, testing and pre-commission cleaning
  • application of a correct and appropriate water treatment programme
  • effective management of the programme

A steering group comprising of BSRIA, the Water Management Society, the Commissioning Specialists Association and the United Kingdom Water Treatment Association, have complied the technical content within the report.

The guidance is consistent with (BG 29/2012) Pre-Commission Cleaning of Pipework Systems, BS 8552:2012 Sampling and monitoring of water from building services closed systems. Code of practice and the European Biocidal products Regulation (528/2012, commonly known as BPR).

Hard copies of the guide are now available to order at the pre-launch price of £50 for non-members or £25 for BSRIA members until 22nd November. PDF versions are free to download for BSRIA members and priced at £50 + VAT to non-members. Full price for hard copies of the guide is £60 to non-members and £30 to BSRIA members.

For a full description of the guide please visit the BSRIA website by clicking here.

Download the guide here.

References:
BSRIARAC Plus

This article is brought to you by Fridgehub – a major new industry website for manufacturers, distributers, service providers, operators and consumers of refrigeration, air conditioning and heat-pump (RACHP) products and services.

www.fridgehub.com

Follow @theFridgehub on Twitter

Subscribe to Fridgehub Industry News Updates

Fitting adiabatic cooling to your air-cooled refrigeration plant will improve its efficiency and save you both energy and money.

Adiabatic cooling involves spraying water into the air supply of an air-cooled condenser to pre-cool the air. Cooler air increases the effective capacity of the condenser, which reduces the work required of the refrigeration compressor.

This means that your system will consume less energy, saving you money. You’ll make most of your savings during warm weather –adiabatic cooling is usually turned off when it’s cold.

The business case - The cost of installing an adiabatic cooling system depends on the size of the condenser. As a general rule you’re likely to recoup your investment within two years.  An added advantage is that the reduced load on the compressor lengthens its lifespan and cuts maintenance costs. However, the system does consume water, so you’ll have to take into account increased water costs.  A 300kW chiller will cost around £2,000 to install.  Based on 1,500 operating hours per year, it will save you around £1,400 a year, giving a payback period of 1.4 years.

How to add adiabatic cooling to your refrigeration plant (CTL139) – Click to view

Further information on the Carbon Trust guidance documents click here.

Speaking at the ATMOsphere Europe 2013 Conference held in Brussels last week John Skelton F.Inst.R., Head of Refrigeration at Sainsbury’s, outlined the Company’s progress with regard to the installation of environmentally friendly RACHP technologies within their stores.
This includes:

167 CO2 refrigeration installations

17 LED lighting installations

78 Biomass boilers

12 Closed Loop Geothermal Heating and Cooling Systems

129,000 Solar panels

25% of Petrol Station energy from solar photovoltaic panels (PV)

These initiatives form part of Sainsbury’s 20x20 Sustainability Plan of which ‘Respect for our environment’ is a key objective.

John Skelton joined Sainsbury’s Supermarkets Limited as an apprentice in 1984. He has spent his career in retail refrigeration working for and on behalf of various UK food retailers. He has been instrumental in reducing Sainsbury’s carbon footprint and the step change to CO2 refrigeration. John has delivered CO2 to over 160 stores and continues to champion the switch to natural refrigerant solutions.

The presentation can be viewed here:

ATMOsphere presentation

In the first Fridgehub article on the subject of Geothermal/Ground Source Heat Pumps (18th September 2013) we outlined Sainsbury’s initiative to use this innovative technology to tap renewable energy from deep underground to provide energy efficient heating, hot water and cooling in a growing number of their supermarkets.

Fridgehub are privileged to have been granted permission by the Institute of Refrigeration to publish a case study written by John Skelton entitled “Closed Loop Geothermal Heating and Cooling for Supermarkets”.

In his introduction to the case study the author states that “The development of a closed loop geothermal heating and cooling system provided the ideal vehicle for Sainsbury’s to manage a store’s total carbon emissions whilst driving operational excellence”.

The case study describes the installation and energy performance of the integrated solution at Sainsbury’s store at Crayford, South East London (their first 100,000 sq. /ft. store)”.

Crayford was selected as a trial ‘carbon step change store’ as part of the Sainsbury’s business challenge to develop a lower carbon operational model. During 2010 the store’s sales area was being extended from 35,000 sq. /ft. to over 100,000 sq. /ft. and the challenge was set to achieve a zero absolute increase in the original store’s operational carbon footprint. An integrated geothermal system was selected to harness normally wasted store energy and to use it efficiently across the refrigeration and heating systems.

A key feature of this solution was that it required all of the delivery teams to change their normal ways of working from a design, installation and commissioning perspective. It was essential that the supply base drove the specification and worked collaboratively. In particular the collaboration between the disciplines of Refrigeration and Mechanical & Electrical engineering was critical to a successful outcome.

The system incorporates a primary circuit closed loop borehole system which provides access to the geothermal storage capacity of subsurface geology, adapting technology from the oil and gas drilling industry to utilise 15 x 200m deep boreholes.

The primary circuit which links the below ground boreholes to the refrigeration packs and the store heat pumps is filled with a glycol-water mix which exchanges geothermal energy due to the temperature differential with the surrounding geology. Due to the natural, relatively cool temperature of the ground a good condensing or cooling medium is delivered to the store’s refrigeration packs and heat pumps.

A secondary circuit delivers the store heating functions from the heat pumps, the performance of which is assisted by the rejected heat from the refrigeration packs.

The refrigeration packs are ‘standard’ Sainsbury’s CO2 with the addition of water to refrigerant heat exchangers in the refrigeration discharge circuit.

The heat pumps are fitted with water to refrigerant heat exchangers. The evaporator is supplied with the glycol-water mix from the borehole circuit, providing low grade heat. The condenser is connected to the store heating and hot water system and high quality heat produced by the compressors is rejected into a standard water-based circuit within the store which has enabled the requirement for natural gas to be discontinued.

Each of the working systems are sub-metered and monitored utilising the Sainsbury’s standard web-based system which enables both historical and cross-store comparisons. To ensure accuracy BSRIA were employed to check all of the monitoring points and calibrate and verify them, as well as to check the reporting/calculation methodology.

The first full year’s operation at Crayford delivered approximately a 55% energy saving in heating and refrigeration against an agreed benchmark for a like-sized store utilising standard systems (i.e. air-cooled CO2 refrigeration packs and gas boilers for heating).

The installation demonstrates that there are tangible benefits from considering a building’s carbon emissions as a ‘whole’ and ensuring the different engineering disciplines work together to reduce direct and indirect emissions, highlighting Sainsbury’s collaborative supplier philosophy.  The Closed Loop Geothermal Heating and Cooling system at Crayford has delivered significant savings in refrigeration energy consumption, as well as a highly efficient ground source heating system to the store.

From the outset, this design concept was intended to be both sustainable and replicable, and as a result of the experience at Crayford the systems has now been implemented in an additional 11 Sainsbury’s stores during the past 3 years making a significant contribution to their 20 by 20 target of a 30% reduction in absolute operational carbon emissions by 2020 versus a baseline of 2005.

The IoR article can be viewed here:

Closed loop refrigeration

Acknowledgements:

  • ATMOsphere European Conference 2013
  • John Skelton F.Inst.R
  • The Institute of Refrigeration

Many case study sessions that focus on cutting-edge natural refrigerant technologies and projects in the areas of industrial, commercial and transport refrigeration as well as heat pumps and air-conditioning were included at the ATMOsphere Europe 2013 Conference.

The full range of presentations from ATMOsphere Europe can be found on www.ATMO.org.

This Refrigeration Road Map introduces the main energy saving opportunities for refrigeration use in the retail sector and demonstrates how simple actions save energy use, cut costs and increase profit margins.

The technologies included in the Refrigeration Road Map have been divided into three sub-groups:

  • Technologies currently available for retrofit in supermarkets
  • Technologies that could be installed during a store refit
  • Technologies that could be implemented in a new build supermarket.

Each technology has then been benchmarked against a baseline supermarket scenario to show its relative carbon saving potential. In addition, a number of potential future technologies have also been identified. These technologies are discussed within this report, but have not been evaluated for their CO2e saving potential as there is currently insufficient evidence to attribute carbon savings to them at this stage in their development.  This report accompanies the Refrigeration Road Map and is split up into a number of sections:

  • How the Refrigeration Road Map was developed.
  • How the Refrigeration Road Map should be used.
  • The presentation format for the Refrigeration Road Map.
  • The baseline supermarket used for making carbon calculations.
  • The Refrigeration Road Maps for the three technology subgroups (retrofit, refit and new store), together with an explanation of each technology.
  • Details on other future potential technologies that could save carbon but are not currently considered viable in the short to medium-term.

Refrigeration road map (CTG021)Click to view

For more information about the Carbon Trust guidance documents, click here.

NIIRTA, Northern Ireland Independent Retail Trade Association, is the representative body for the independent retail sector in Northern Ireland. With over 1,300 retail members from wholesalers to independent retailers and a wide variety of suppliers within the sector, the collective membership employs more than 30,000 staff and has an annual turnover of over £3 billion.

NIIRTA members spend an estimated £15 million per year on energy. This equates to an annual energy spend of £19,500 for a 2,000 ft2 sales area convenience store, going up to £25,000 or even £45,000 if the store uses more than the average amount of energy, or is open 24 hours a day. Refrigeration has been identified as the largest energy user in convenience stores. Considering 50-70% of a supermarket’s energy costs can be attributed to refrigeration, a conservative estimate indicates that £7.5 million is spent by NIIRTA members on refrigeration. This equates to between £9,750 and £22,500 per year per store.

This guide will allow NIIRTA members to implement efficiency improvements through 41 opportunities classified by scale of implementation from:

  • Day to day operations.
  • At the Next Engineer Service.
  • Part of Refurbishment/Retrofit.
  • Full Replacement.

For more information on the Energy Savings in Retail Refrigeration guide – Click to view.

If you would like to view further Carbon Trust guidance documents, please click here.

The Carbon Trust provides simple, effective advice to help businesses take action to reduce carbon emissions.

Improve energy efficiency of your refrigeration systems with energy-saving guidance in a series of handy guides from the Carbon Trust.

This refrigeration technology guide introduces the main energy saving opportunities for businesses and demonstrates how simple actions can save energy, cut costs and increase profit margins.  Energy saving doesn’t need to be expensive. Up to 20% can be cut in many refrigeration plants through actions that require little or no investment.

In addition, improving the efficiency and reducing the load on a refrigeration plant can improve its reliability and reduce the likelihood of a breakdown. Most organisations can save energy and money on refrigeration through good maintenance, housekeeping and control and more efficient equipment.

This publication provides an overview of the operation of refrigeration systems, identifies where you can make savings, and will help you to present an informed case on energy savings to key decision makers within your organisation.

If you would like to find out more about the Refrigeration systems technology guide (CTG046)Click to here.

You can view further Refrigeration guidance documents from the Carbon Trust here.

 

Improve energy efficiency of your refrigeration systems with energy-saving guidance in a series of handy guides from the Carbon Trust.

For some organisations refrigeration costs can represent over 50% of their energy bill. The Carbon Trust provides simple, effective advice to help businesses take action to reduce carbon emissions. The simplest way to do this is to use energy more efficiently.  We recommend the following refrigeration guidance documents from the Carbon Trust:

 

Refrigeration guidance: We have the following refrigeration publications available for free download:

Refrigeration systems technology guide (CTG046)

Refrigeration systems technology guide

Refrigeration systems technology guide (CTG046) – Click to view

This refrigeration technology guide introduces the main energy saving opportunities for businesses and demonstrates how simple actions can save energy, cut costs and increase profit margins.  Energy saving doesn’t need to be expensive. Up to 20% can be cut in many refrigeration plants through actions that require little or no investment. In addition, improving the efficiency and reducing the load on a refrigeration plant can improve its reliability and reduce the likelihood of a breakdown. Most organisations can save energy and money on refrigeration through good maintenance, housekeeping and control and more efficient equipment.  This publication provides an overview of the operation of refrigeration systems, identifies where you can make savings, and will help you to present an informed case on energy savings to key decision makers within your organisation.

Energy Savings in Retail Refrigeration (CTG808)

Chilling energy costs

Energy Savings in Retail Refrigeration (CTG808) Click to view

NIIRTA, Northern Ireland Independent Retail Trade Association, is the representative body for the independent retail sector in Northern Ireland. With over 1,300 retail members from wholesalers to independent retailers and a wide variety of suppliers within the sector, the collective membership employs more than 30,000 staff and has an annual turnover of over £3 billion.

NIIRTA members spend an estimated £15 million per year on energy. This equates to an annual energy spend of £19,500 for a 2,000 ft2 sales area convenience store, going up to £25,000 or even £45,000 if the store uses more than the average amount of energy, or is open 24 hours a day. Refrigeration has been identified as the largest energy user in convenience stores. Considering 50-70% of a supermarket’s energy costs can be attributed to refrigeration, a conservative estimate indicates that £7.5 million is spent by NIIRTA members on refrigeration. This equates to between £9,750 and £22,500 per year per store.

This guide will allow NIIRTA members to implement efficiency improvements through 41 opportunities classified by scale of implementation from:

  • Day to day operations.
  • At the Next Engineer Service.
  • Part of Refurbishment/Retrofit.
  • Full Replacement.

Refrigeration road map (CTG021)Click to view

Refrigeration Road Map

Refrigeration road map (CTG021) Click to view

This Refrigeration Road Map introduces the main energy saving opportunities for refrigeration use in the retail sector and demonstrates how simple actions save energy use, cut costs and increase profit margins.

The technologies included in the Refrigeration Road Map have been divided into three sub-groups:

  • Technologies currently available for retrofit in supermarkets
  • Technologies that could be installed during a store refit
  • Technologies that could be implemented in a new build supermarket.

Each technology has then been benchmarked against a baseline supermarket scenario to show its relative carbon saving potential. In addition, a number of potential future technologies have also been identified. These technologies are discussed within this report, but have not been evaluated for their CO2e saving potential as there is currently insufficient evidence to attribute carbon savings to them at this stage in their development.  This report accompanies the Refrigeration Road Map and is split up into a number of sections:

  • How the Refrigeration Road Map was developed.
  • How the Refrigeration Road Map should be used.
  • The presentation format for the Refrigeration Road Map.
  • The baseline supermarket used for making carbon calculations.
  • The Refrigeration Road Maps for the three technology subgroups (retrofit, refit and new store), together with an explanation of each technology.
  • Details on other future potential technologies that could save carbon but are not currently considered viable in the short to medium-term.

How to maintain refrigeration equipment (CTL135)

How to ensure your equipment is correctly maintained

How to maintain refrigeration equipment (CTL135)Click to view

Correctly maintaining your refrigeration equipment can save you energy and money, as well as reducing downtime. This guide should help you ensure your maintenance arrangements maximise energy efficiency and minimise costs.  All refrigeration equipment needs to be serviced to repair faults, and maintained to prevent faults before they happen. Appropriate plant maintenance will save you money through reduced energy bills, reduced service costs and less plant downtime. Appointing a good maintenance contractor is the key to achieving these savings.

The business case

Good maintenance saves money by maximising plant efficiency and therefore reducing electricity costs, reducing equipment failure and the costs associated with plant downtime and stock or product loss.  The cost of a suitable maintenance contract depends on the complexity and size of the system. Typically the annual maintenance cost is between 2% and 5% of the original capital cost of the plant, but you’re likely to save up to 10 times the maintenance cost through greater energy efficiency. In addition you can also reduce service costs and lost production costs.

How to minimise head pressure in refrigeration (CTL136)

How to minimise head pressure in refrigeration

How to minimise head pressure in refrigeration (CTL136) – Click to view

By minimising the head pressure of your existing refrigeration systems, you can increase their efficiency and cooling capacity, and save yourself both energy and money.  Head pressure refers to the pressure in the high pressure side of a refrigeration system – the condenser.  Lowering head pressure reduces the temperature at which the condenser operates and increases the efficiency of your refrigeration system. By minimising the head pressure, you can maximise your system’s cooling capacity and minimise energy costs.

All refrigeration systems, from small integral standalone equipment such as domestic refrigerators, to those with condensing units or remote condensers, can have the potential to reduce head pressure. This guide is most relevant if you have a system with a condensing unit, or a remote air-cooled or evaporative condenser.

How to reduce heat gain in refrigeration (CTL137)

How to reduce heat gain for cabinets and cold rooms

How to reduce heat gain in refrigeration (CTL137)-Click to view

Minimising the heat gains on refrigerated cabinets and cold rooms cuts the cooling load on your refrigeration system and saves you energy and money. Any energy efficiency initiative dealing with refrigeration should start by reviewing the heat gains on your system.  If you understand the nature of these gains, you’ll be able to manage the amount of cooling that needs to be done and make energy savings. Heat gains include warm air entering the cabinet or cold room and heat produced by electrical equipment within the cooled space. This guide covers in detail two opportunities to reduce heat gains: reducing cold air changes using strip curtains, and using EC (electronically commutated) replacement motors for evaporator fans.

The business case - You will find opportunities for reducing heat gains on refrigerated cabinets and cold rooms in most applications.  Improving door management in cold rooms results in substantial energy savings. For example, installing plastic strip curtains to a cold room can give savings of up to 30%, and have a payback period of around a year.  Replacing conventional shaded-pole fan motors with equivalent EC motors can cut their energy use by 65%, as well as generating less heat and reducing your maintenance replacements.  You can maximise the saving achieved by fitting a whole new fan assembly instead of just replacing the motor. In most applications the payback period for fitting EC motor fans is one to two years, but it can be much shorter.

How to reduce heat load in refrigeration (CTL138)

How to reduce your heat load

How to reduce heat load in refrigeration (CTL138) – Click to view

Reducing the heat load on your existing large refrigeration systems can save energy and cut your running costs. It can also reduce the capital cost of a new plant and even eliminate the need to invest in a new plant altogether.  This guide is aimed at users of existing large refrigeration systems such as those in supermarkets, central air conditioning systems, large cold stores and large industrial processes. It will help you to minimise your cooling needs and to meet them as efficiently as possible using the most suitable refrigeration system.  Both of these will result in energy savings.

Before you start any refrigeration energy efficiency initiative it is vital to review the heat loads on your cooling plant. If you understand the nature of your loads you can make sure they are met while at the same time minimising the energy cost of your refrigeration systems.

The business case - There are opportunities to reduce the heat load on refrigeration systems at almost all sites.  Savings and costs will vary depending on the type of opportunity.  Often payback periods are less than one year, and sometimes even no-cost heat load reductions are possible.  If you are planning to install a new plant, reducing its heat load could reduce the capital cost. If your existing refrigeration system currently struggles to supply enough cooling, reducing the heat load on your system could avoid the need for an expensive new plant altogether.

How to add adiabatic cooling to your refrigeration plant (CTL139)

How to add adiabatic cooling to your refrigeration plant

How to add adiabatic cooling to your refrigeration plant (CTL139) – Click to view

Fitting adiabatic cooling to your air-cooled refrigeration plant will improve its efficiency and save you both energy and money.  Adiabatic cooling involves spraying water into the air supply of an air-cooled condenser to pre-cool the air. Cooler air increases the effective capacity of the condenser, which reduces the work required of the refrigeration compressor.  This means that your system will consume less energy, saving you money. You’ll make most of your savings during warm weather –adiabatic cooling is usually turned off when it’s cold.

The business case - The cost of installing an adiabatic cooling system depends on the size of the condenser. As a general rule you’re likely to recoup your investment within two years.  An added advantage is that the reduced load on the compressor lengthens its lifespan and cuts maintenance costs. However, the system does consume water, so you’ll have to take into account increased water costs.  A 300kW chiller will cost around £2,000 to install.  Based on 1,500 operating hours per year, it will save you around £1,400 a year, giving a payback period of 1.4 years.

How to implement heat recovery in refrigeration (CTL056)

How to implement heat recovery in refrigeration

How to implement heat recovery in refrigeration (CTL056) – Click to view

Recovering waste heat produced by the refrigeration process can save energy and cut costs.  Industrial and commercial companies of all sizes and in all sectors use refrigeration plant to reduce the temperature of buildings.  The food industry also uses refrigeration in the production and storage of food and drink.  Heat recovery equipment can be fitted to existing plant, or companies can specify new plant with heat recovery already integrated. In both cases, the technology allows waste heat to be re-used for space heating or hot water.

The business case - The cost depends on size, but even on some small units, companies could recoup their investment in less than five years.  For a 200kW chiller, heat recovery equipment would cost around £10,000 installed. Assuming 3,000 hours’ operating a year and current gas prices, the heat recovered could add up to a saving of £5,400 – giving a payback in less than two years.  A new 150kW capacity chiller with full heat recovery would be around £26,000 installed, but operating on the same number of hours as above, could save £13,500 and give a payback in around two years.

This article is brought to you by Fridgehub – a major new industry website for manufacturers, distributers, service providers, operators and consumers of refrigeration, air conditioning and heat-pump (RACHP) products and services.

www.fridgehub.com

Follow @theFridgehub on Twitter

A geothermal heat pump or ground source heat pump (GSHP) is a central heating and/or cooling system that pumps heat to or from the ground.  Ground source heat pumps harvest heat absorbed at the Earth's surface from solar energy.  It uses the earth as a heat source (in the winter) or a heat sink (in the summer). This design takes advantage of the moderate temperatures in the ground to boost efficiency and reduce the operational costs of heating and cooling systems, and may be combined with solar heating to form a geosolar system with even greater efficiency. Ground source heat pumps are also known as "geothermal heat pumps" although, strictly, the heat does not come from the centre of the Earth, but from the Sun.

Ground source heat pumps use pipes which are buried in the ground to extract heat from the ground. This heat can then be used to heat radiators, underfloor or warm air heating systems and hot water in a building.

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 the ground outside the building. Heat from the ground is absorbed into the fluid and then passes through a heat exchanger into the heat pump. The ground stays at a fairly constant temperature under the surface, so the heat pump can be used throughout the year – even in the middle of winter.

The length of the ground loop depends on the size of the building and the amount of heat needed. 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.

The benefits of installing a ground source heat pump (GSHP) include:

  • Lower fuel bills, especially when replacing conventional electric heating systems
  • Could be eligible for income through the government’s Renewable Heat Incentive (RHI*) for non-domestic buildings
  • Lower the building’s carbon emissions, depending on which fuel you are replacing
  • Can be used to heat and provide hot water
  • Needs little maintenance – GSHP’s are known as ‘fit and forget’ technology.
  • Renewable Heat Incentive – Commercial RHI - Owners of ground source heat pumps systems (and other eligible renewable heat technologies) installed since 15 July 2009, can apply to Ofgem to be paid around 10 pence/kWhour of renewable heat generated for the next 20 years.

Unlike gas and oil boilers, heat pumps deliver heat at lower temperatures over much longer periods. During the winter they may need to be on constantly to heat the building efficiently. Occupants will also notice that radiators won't feel as hot to the touch as they might do when using a gas or oil boiler.

Heat from the ground is absorbed at low temperatures into a fluid inside a loop of pipe (a ground loop) buried underground. The fluid then passes through a compressor that raises it to a higher temperature, which can then heat water for the heating and hot water circuits of the house. The cooled ground-loop fluid passes back into the ground where it absorbs further energy from the ground in a continuous process as long as heating is required.

Normally the loop is laid flat or coiled in trenches about two metres deep, but if there is not enough space a vertical loop down into the ground can be installed to a depth of up to 100 metres.  Heat pumps have some impact on the environment as they need electricity to run, but the heat they extract from the ground, the air, or water is constantly being renewed naturally.

In July, retail giant Sainsbury’s launched the installation of their 12th Ground Source Heat Pump at their store at London Colney in St. Albans.  They have showcased their use of this innovative technology that taps renewable energy from deep underground to provide energy efficient heating, hot water and cooling for the stores.  The roll out of Ground Source Heat Pumps at 12 stores follows Sainsbury’s successful world-first use of the geo-thermal technology at its Crayford store, enabling it to supply 30 per cent of its energy from on-site renewable sources.  It has also installed 74 biomass boilers since 2008, which use wood pellets - a renewable resource - to heat stores rather than using fossil fuel-based gas.

GSHP Resources

The Ground Source Heat Pump Association - The Association provides information on GSHPs via a this website and telephone helplines and makes presentations to promote the ground source industry to key audiences.

Energy Savings Trust – Advice to homeowners on Ground Source Heat Pumps, installation, financial benefits, Planning permissions.

B&ES - Ground Source Heat Pump Guidance - Great resources that will provide more detail on Ground Source Heat Pumps

B&ES – TR 30 - The first part of the forthcoming suite of TR30 publications, this looks at different applications of Heat Pumps technology.  It provides generic installation requirements for a range of renewable energy systems including biomass fuels, solar hot water and combined heat and power (CHP).

Ground source heat pump

Image Credit: Advance NRG www.advancenrg.com

This article is brought to you by Fridgehub – a major new industry website for manufacturers, distributers, service providers, operators and consumers of refrigeration, air conditioning and heat-pump (RACHP) products and services.

www.fridgehub.com

Follow @theFridgehub on Twitter