Heat Pumps Today

Info www.climalife.co.uk www.acrjournal.uk/heat-pumps 15 R E F R I G E R A N T S some specialist heat pump applications, R-744, R-1233zd, Propane and Ammonia are being used as a refrigerant. Using a heat transfer fluid within the heat pump system The air source, ground source and water source heat pump systems all use a heat transfer fluid, whether it be a glycol solution or water, and heat it in the heat exchanger, using the compressed refrigerant, raising its temperature so that it is suitable for the system. In the case of a ground source heat pump system for example, the heat transfer fluid or glycol is circulated through a set of underground pipes, also known as a ground loop. A closed-loop GSHP system circulates heat transfer fluid through a closed loop set of underground pipes, whereas an open-loop system uses ground water for the heat exchange process and extracts it after use. Open loops tend to be simpler and cheaper to install however may require more maintenance. As the ground has a relatively constant temperature through the year, it is considered an excellent source of heat. The Ground Source Heat Pump Association report the natural temperature of undisturbed ground in Britain to be around 10°C at a depth below six metres, although temperature will depend on location and depth. So, to some extent, the HTF has a head start on its heating. All heat pumps require electricity to operate but can provide very energy e‹cient heat with high coe‹cient of performance (COP) values of up to 5, whereas the best condensing boilers can only deliver a COP of 0.9. Bio-sourced HTF alternatives Traditionally, heat transfer fluids, used in the food, building and energy industries have been based on mono propylene glycol (MPG) a product from the petrochemical industry. With this tighter focus on carbon reduction targets, and increasing environmental commitments, it’s time to consider the available alternatives to conventional heat transfer products. One such product being Greenway® Neo N; a plant-based heat transfer fluid which has been formulated with bio-sourced 1,3 propanediol. Plants are harvested, fermented and refined to produce this biotechnology. By using a product such as Greenway® Neo N Heat Pump which is biodegradable, there is the reduced risk of soil pollution in the event of a leak, which is particularly important in a heat pump system, and excellent corrosion protection. It’s bacteriostatic formula, prevents the development of bacteria, moulds, fungus and algae which can ašect the flow and heat exchange, so it helps to reduce clogging and e‹ciency can be maintained by a good flow rate. Notably, the production process of bio-sourced 1,3 propanediol consumes less energy and emits less CO 2 during manufacture than MPG or synthetic chemicals, helping to reduce environmental footprint. Case study air source heat pump system in the 40m² orangery of a local farmland owner in Northamptonshire, using Greenway® Neo throughout as the HTF. The heat pump is linked directly to a Polypipe ‘In-Screed’ system comprising of a 4-port manifold supplying 18mm underfloor heating pipe secured with castellated floor trays. The pipe was laid at 100mm spacing in a spiral pattern ensuring a comfortable even floor temperature and as low as possible HTF flow temperature whilst still satisfying the buildings heat loss demand. In this case the air oš temperatures varied between 35°C and 45°C, and so by running an air source heat pump at the lowest temperature possible, the maximum operating e‹ciency (SPF) was ensured. The building owner was keen to promote the usage of renewable energy and products, which fits in with the local focus; one of the largest onshore Wind and Solar Farms in the country being situated nearby. An R32 Daikin heat pump AC unit was also installed for the orangery by Gri‹ths. Gri‹ths AC continue to use Greenway® Neo as their standard heat transfer fluid for all their installations, including Solar Thermal systems, Ground and Air source heat Pumps, Monoblock systems and also for underfloor heating. Their technical manager said ‘The choice to use Greenway® Neo was easy, we only need one product, and we chose the most environmentally acceptable product on the market, which fits our company policy to use renewable products wherever possible’. Time for change It's been interesting to see heat pump systems beginning to be advertised on mainstream television, which highlights how heat pumps will soon become our everyday norm. So, with sustainability at the heart of the shift, it’s important to be aware of the energy e‹cient refrigerants that are available and the alternative bio- sourced htf alternative(s) to MPG and MEG. If you would like to find out more about these fluids, consider speaking to Climalife or contact your usual supplier. Climalife prides its expertise in eco-e‹cient solutions to service the industry and works with many heat pump installers, supporting them with refrigerants and heat transfer fluids, suited to each individual project. One such installer being Gri‹ths Air Conditioning and Electrical Contractors, an MCS accredited installer of Air and Ground source heat pump systems. Gri‹ths AC installed a Daikin 8KW Altherma Monobloc