BSEE BOILERS & HOT WATER
Hot water is a convenience that comes with its down sides, not least the high environmental price tag that is usually aached. Herve Mariage, Product Manager, Mitsubishi Heavy Industries, believes airtowater heat pumps may be the answer to a more convenient and sustainable hot water supply.
drive for environmental protection and sustainability.
H
The amount of energy it takes to heat water, particularly in large commercial buildings such as hospitals and hotels, is vast and can have a huge impact on the environment. For instance, R410a, a refrigerant widely used in heat pumps, has a Global Warming Potential (GWP) of 2088.
As sustainability and environmental footprints become a more important priority in building design and construction, organisations have started to highlight the impact that construction has on the environment. The Committee on Climate Change revealed in June 2017 that commercial buildings are responsible for 3% of the UK’s greenhouse gas emissions alone.1 This, against a backdrop of more stringent emission-reduction targets, has meant that regulators are applying ever-increasing pressure on businesses and operators of commercial properties are under particular scrutiny. They must reduce their environmental footprint to avoid penalties such as carbon taxes, hitting their profits.
Sustainable soluons
uMitsubishi Heavy Industries Air Condioning’s Qton system uses CO2
dramac savings in CO2 and costs.
as a refrigerant and achieves emissions
However, there is a solution. There is no need to compromise on this every-day essential while making buildings (and the businesses operating within) more environmentally friendly and efficient. The answer lies in air-to-water heat pumps. These absorb heat from the outdoor air and use compressed carbon dioxide to generate sanitary hot water without the need for an immersion heating element. This not only drastically reduces the overall Global Warming Potential (GWP) rating, but specifically decreases the carbon footprint of a new building. Mitsubishi Heavy Industries Air Conditioning’s Q-ton system, an air-to- water heat pump which uses CO2
as a
refrigerant, achieves two goals in one: dramatic savings in CO2
emissions and costs. These amount to 45% less carbon
igh power usage and associated
greenhouse emissions put water boilers and immersion heaters at odds with the global
Adversing: 01622 699116 Editorial: 01354 461430
AIRTOWATER HEAT PUMPS A convenient and sustainable solution
and a cost saving of nearly 40% when compared to a traditional water boiler. When matched against immersion heaters, the savings are nearly double those figures.
At the same time, the use of carbon dioxide as a refrigerant reduces the GWP of heat pumps, such as the Q-ton, to 1GWP and preserves the ozone layer with an Ozone Depletion Potential (ODP) of zero. As a result the Q-ton also falls outside the F-gas regulations. For every 1kW of input, an electric immersion heater will generate 1kW in output, while a heat pump can generate more than three times that amount at 3.5kW. High performance heat pumps, such as the Q-ton, can produce water at temperatures between 60-90ºC throughout a large commercial building, even with outside temperatures as low as -25ºC. Additionally, systems can be set up to meet specific requirements, from one 30kW Q-ton unit providing 6,000 litres of hot water a day, to 16 heat pump units in a modular configuration of 480kW, connected to substantial hot water storage tanks for larger applications. The high efficiency, performance and sustainability of heat pumps, compared with electric immersion heaters, can help buildings comply with various
environmental regulations across markets, without compromising on output.
In pracce
Proof of this balance was seen in the Lancaster Hall Hotel in London. Operating in a building where the demand for hot water was high – with 80 guest rooms and a total of 250 people on site – the Q-ton was put to the test to improve the building’s environmental efficiency and reduce running costs, without compromising on the supply of hot water.
By connecting two Q-ton pumps to two 2,000 litre hot water storage tanks, the hotel was able to meet the demand of supplying 12,000 litres per day of domestic hot water at 65ºC for guests and employees. This technology has resulted in the hotel saving up to 40% in running costs compared to their previous boiler and has delivered a reduction of 45% in carbon emissions.
Another example of the Q-ton handling large scale hot water needs efficiently can be found at the University of Bristol. As most halls of university residence within the UK use expensive conventional electric immersion elements for heating water, the site energy manager was looking for a sustainable replacement. Working closely with ASHP and engineering consultants, the Q-ton pump was installed to provide sanitary hot water at an accommodation block facilitating up to 48 students from September through to July. The system is now fully operational and delivers 2,500 litres per day of sanitary hot water at 65°C. Q-ton is currently reducing the annual running costs by 75% and saving CO2
emissions by 67%.
Environmental regulations are driving developers and operators to design more energy-efficient buildings. Sustainable and efficient appliances that manage carbon emissions and reduce operating costs are therefore an increasingly important consideration for commercial developers. UK policy is supporting this by providing a financial incentive to companies. Through the Enhanced Capital Allowances (ECA) scheme, businesses that buy products meeting the high energy efficiency standards set out in the Energy Technology List scheme, are able to receive accelerated tax relief on the purchase of that equipment. Therefore, heat pumps, such as the Q-ton, which use carbon dioxide as the refrigerant and qualify for ECA, play a large role in reducing the carbon footprint and increasing the energy efficiency of commercial buildings. The Q-ton can be considered a replacement for solar thermal panels and is more reliable than them at producing constant set hot water temperatures. Heat pumps may well be the missing link between convenience and sustainability and should be considered when it comes to designing energy efficient buildings.
www.mhiae.com
Committee on Climate Change (June 2017) Meeting Carbon Budgets: Closing the policy gap.
1 ‘
Airtowater
heat pumps absorb heat from the outdoor air and use compressed carbon dioxide to generate sanitary hot water without the need for an immersion heang element. This not only drascally reduces the overall Global Warming Potenal (GWP) rang, but specifically decreases the carbon footprint of a new building.
’
uBy connecng two Qton pumps to two 2,000 litre hot water storage tanks, the Lancaster Hall Hotel was able to supply 12,000 litres per day of domesc hot water at 65°C for guests and employees.
16 BUILDING SERVICES & ENVIRONMENTAL ENGINEER JULY 2018 VISIT OUR WEBSITE:
www.bsee.co.uk
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