Today we installed a super-efficient air source heat pump to cool our production area. We now only use air-source heat pumps for all of our cooling, powered from 100% renewable energy. In short, we have met the UK Government Climate Change Panel May 2019 technical report recommendations for 2050 – thirty years ahead! It is technically possible for all businesses to do this.
As a chocolate company we are perhaps unusual in that we hardly ever need heating, but we do need ambient cooling. As our 10 year old air conditioning unit had expired and been diagnosed as uneconomical to repair we decided to look again at the latest recommendations in cooling (and heating).
We already had two smaller air source heat pumps installed for cooling, but this was the chance to replace a much larger and relatively inefficient cooling unit.
What is an Air Sourced Heat pump?
Air at temperatures above absolute zero (-273 degrees C) contains some energy. An air-source heat pump transfers some of this energy as heat from one place to another. In our case heat is taken from the inside of our building to the outside to cool our production area. Thus we have two units, an indoor unit and an outdoor unit.
The failed non heat pump Air conditioning unit worked on simple on – off control of the outdoor compressor unit such that the cooling fan either ran at full speed or not at all.
A more efficient operation varies the speed of the rotor proportionally to match the heat transfer requirements. This is achieved through inverter control of the fan speed. Our other two outdoor units already used inverter technology and had worked well.
What do the Government think?
In May 2019 the UK government Committee on Climate change made the following technical report recommendations to meet net zero carbon…
“A scenario of the installation of 2 million heat pumps, partially offsetting electricity grid demand increases by energy efficiency improvements.
That where heat is electrified it is done efficiently through heat pumps – which can produce more than three units of heat per unit of electricity – rather than resistive or immersion heating (which only produce one unit).
The scenarios include improvements in heat pump efficiency over time, towards an average heat pump coefficient of performance (COP) of three in 2050 (providing three units of heat per unit of electricity). Further improvements in heat pump efficiency could reduce demand from electrified heat.”
With this in mind we researched the available air sourced heat pump technology. Air sourced heat pumps can cool as well as heat.
REFRIGERANT OZONE DEPLETION POTENTIAL GLOBAL WARMING POTENTIAL
R-22 MEDIUM 1810
R-32 NO 675
R-134A NO 1430
R-410A NO 2088
The gas we have chosen is the newest available gas and also the most efficient – R32. However that still has a Global Warming Potential (GWP) of 675 times that of Carbon Dioxide. Worrying if it should leak or not be disposed of in the correct way at end of machinery life or during maintenance.
The Toshiba Digital Inverter unit we have chosen already has a Coefficient of Performance (COP) of 3.62, so already exceeding the 2050 target. Our smaller existing heat pump cooling units are also very efficient and the average is over the 2050 recommendation of 3.0. So we have met the Climate Change Panel target 30 years ahead of time!
The main advantage here is we get 3.62 kW of cooling power for every 1kW of electricity used.
The capital expenditure of installing the Heat pump can also be offset against profits in the UK via the Annual Investment Allowance scheme.
For those more interested in heating than cooling there is a currently a Renewable Heat Incentive (RHI) available in the UK.
The Energy Savings Trust (https://www.energysavingtrust.org.uk) says the following about Air Source Heat Pumps…
The benefits of air source heat pumps are :-
-Lower fuel bills, especially if you are replacing conventional electric heating potential income through the UK government’s Renewable Heat Incentive (RHI)
– lower home carbon emissions, depending on which fuel you are replacing
– no fuel deliveries needed
– can heat your home as well as your water
– minimal maintenance required
– can be easier to install than a ground source heat pump.
– Unlike gas and oil boilers, heat pumps deliver heat at lower temperatures over much longer periods.