HEAT PUMPS | PROPANE REFRIGERANT DHW circuit with either integral or loose three-way valve option Lay acknowledges that some people may be wary of a propane refrigerant, based on its association with fires and barbecues and other gas-fired equipment. However, he adds: The heat pump contains a limited charge of propane, which is not burnt but reused, with autonomous detection of leaks (at 10% lower flammability limit) coupled with a power shut down and ventilation procedure. Propane has already been widely used in the retail sector, but is very new on the HVAC scene, so there may be some pushback [by potential customers]. Lay says the best approach is to give people confidence in how any propane refrigerant leak will be managed, while installers may be more comfortable employing specialist consultants to verify or sign off propane installations and complete site-specific risk assessments. The Geyser Sky Hi HP R0 units come with a dedicated refrigerant leak detector installed, which must be checked at least once a year for correct operation, and recalibrated or replaced where necessary. The installer must also carry out a flammability risk assessment and a classification of a safe installation zone, as required by standard EN378-3, says Lay. Swegon says the unit must not be installed in zones where a risk of stagnant refrigerant may be posed in the event of leakage, with fire extinguishers installed near the unit. Investment While Swegons range promises an environmentally friendlier alternative to a standard gas boiler, ASHPs such as these units currently require more capital expenditure investment than their fossil fuel-based counterparts. Swegons new range is available in three sizes, from 20kW to 30kW, starting at approximately 20,000, depending on the model: the Geyser Sky Hi HP R0 20 provides for peak load of 16.73kW cooling and 19.82kW heating*; the 25 model can deliver 22.5kW cooling and 25.02kW heating; and the 30 offers 27kW cooling and 30.79kW heating* capacity. However, with the reversible units able to deliver We need to invest in getting the message across about air source heat pumps and making it happen both heating and cooling, their space-cooling capability may be an increasingly appealing secondary function as seasonal temperatures rise because of climate change. Lay observes: Historically, weve not been a nation that needs air conditioning or cooling generally, but over the past few years our summers have been getting hotter, and expectations are for that trend to continue. There could be scope for future-proofing [your building] with air conditioning, as well as providing a heating and hot-water system. You get double bang for your buck. Although these units are aimed at light-commercial applications, they have been designed to be user-friendly, with the inclusion of a 4.3 in touchscreen display, so could easily be used in larger residential applications. Lay expects UK demand where the market for ASHPs is far less mature than in Scandinavia to be rooted more in lightcommercial use than in the consumer market. He says the UK market is starting to become familiar with heat pumps and he predicts next year will see a big boom in sales. Within a year or two, he expects natural refrigerants, such as propane, to be in the market. In terms of payback, Lay says current uncertainty surrounding energy prices makes it difficult to determine how soon this can be achieved. Efficiency does ultimately depend on how the units are installed, which is why the biggest focus in our industry needs to be on the installer, he says. As manufacturers, we can tell you what this equipment is capable of doing, and the designers can specify the right units but the crux is when the machine goes in on site. Ensuring optimum performance is crucial, and we need to make sure that happens for customers who are perhaps unsure of the technology and its capability. We need to invest in getting the message across about ASHPs and making it happen. We need support from government to help people understand the new technology what it does and how it works. CJ *Based on EN14511 standards at 12/7/35 for cooling and 40/45/7 for heating 52 November 2022 www.cibsejournal.com CIBSE Nov 22 pp51-52 Swegon heat pump.indd 52 21/10/2022 16:25