Natural refrigerants: The future of low carbon cooling

Whitehall has published a wealth of guidance on the design, installation and operation of specialised building and engineering technology, some of which has implications for the type of heat pumps specified in the commercial sector, particularly hospitals and other medical applications.

HTM 04-01

For example, one of the government’s many memoranda – HTM (Health Technical Memorandum) 04-01 Safe water in healthcare premises – deals with the legal requirements, design applications, maintenance and operation of hot and cold water supply, storage and distribution systems in healthcare premises.

This important document is designed to be read in conjunction with the HSE’s Approved Code of Practice (L8) – The control of legionella bacteria – and HSG274 Part 2 which demands that healthcare facilities ensure a minimum temperature of 55°C at any hot water outlet within one minute without using trace heating.

Carbon dioxide heat pumps = higher hot water temperatures

Maintaining higher hot water temperatures uses more energy, but this is where carbon dioxide (CO2) heat pumps can make a real positive difference. Standard air source heat pumps (ASHPs) using HFC refrigerants typically deliver water at a maximum of 65°C at -4°C ambient with a coefficient of performance (CoP) of around 2.0.

A CO2 ASHP, on the other hand, can deliver an impressive 80°C hot water at -10°C ambient with a CoP of 2.8. In other words, it can deliver higher hot water temperatures at lower ambient temperatures than a conventional heat pump and therefore reduce energy demand.

Reduced legionella risk

But the advantages of CO2 heat pumps don’t end there. Operating at higher temperatures and using the integrated HIT anti-legionella cycle, these devices also reduce the risk of a potentially devastating legionnaires’ disease outbreak in a hospital.

Other big benefits of CO2 heat pumps for domestic / sanitary hot water production in hospitals include energy efficiency, resilience, and reliability.

CO2 being a natural refrigerant brings with it further important advantages. For example, carbon dioxide is an exceptionally eco-friendly refrigerant with a Global Warming Potential (GWP) of 1, being the reference gas against which all other refrigerants are measured, so CO2 heat pumps can considerably reduce harmful greenhouse gas (GHG) emissions.

CO2 is also an excellent refrigerant because it is non-toxic and non-flammable.It is also relatively easy, efficient and sustainable to manufacture.

How does a C02 heat pump work?

But how does a CO2 high-temperature heat pump work? The fundamental principle of heat pumps is to absorb heat at low temperature levels and dispense it as useful heat at a higher temperature. A heat pump uses heat sources that are normally technically unusable for useful heating. For instance, a high-temperature heat pump can take heat from outdoor air at -10degC and deliver it in the form of how water at  90°C or even more. As well as air, it can also employ surface or ground water or lower grade rejected heat as heat sources.

A CO2 high-temperature heat pump especially lives up to its full potential in terms of performance and sustainability when it converts waste heat from industrial production, exhaust air from air conditioning systems, or waste heat from chillers and then makes it available as heat output at a higher temperature level. Because it optimises such processes, using a heat pump generates significant energy savings.

Cutting edge heat pumps

The CO2 heat pump range available from Klima-Therm is a cutting-edge system – a single stage/single source of high temperature hot water production for domestic hot water (DHW), sanitary water or for industrial processes.

Our Enerblue range offers an exceptionally wide heating capacity from 14.5 to 133.2kW, which makes it ideal for a variety of applications (see below). It is powerful enough to heat water to temperatures up to 90°C with an external temperature as low as -20°C.

The units are available in several configurations including air-water, water-water, and air-water with cooling recovery, making them extremely versatile and suitable for installation with any water system.

At a larger scale, our Engie range can provide hot water up to 120°C with up to 1000kW of heat from a single machine.

For more information about our CO2 heat pumps, click here.