EU-funded researchers have found their CO2-based heating and cooling solutions a good fit for stores operating in a southern European climate.
Hydrofluorocarbons (HFCs) are manufactured gases with a wide variety of uses, including refrigeration, air conditioning, aerosols, building insulation and fire extinguishing systems. However, with a global warming potential that is substantially higher than CO2, these fluorinated greenhouse gases (F-gases) cause significant harm to the environment. The 2015 EU F-gas regulation sought to mitigate this impact by reducing the availability of certain HFCs in Europe and citizens’ reliance on them.
To further this goal, the EU-funded MultiPACK project is working to build people’s confidence in new, more environmentally friendly heating and cooling technologies. Introduced as an alternative to F-gases, these next-generation, integrated heating, ventilation, air conditioning and refrigeration (HVAC&R) packages are based on CO2 vapour compression cycles.MultiPACK intends to have its packages installed in supermarkets and other buildings with a high energy demand, such as hotels and gyms. The project team is now testing its heating and cooling solutions in one supermarket in Portugal and two in Italy. The aim is to assess the systems’ technical feasibility, reliability and serviceability, as well as their energy performance in a southern European climate. The three demo systems’ performance is measured using different key performance indicators (KPIs). These include the reduction in peak power and total primary energy demand, the reduction in total CO2 emissions, the reduction in number of cycles of operation of compressors and the reduction in total cost of ownership. Additional KPIs for comparing supermarket performances are the reduction in the number of separate energy transfer units, the operating temperature and pressure of evaporators, and the averaged second law of efficiency.
Preliminary results have shown that the project’s integrated HVAC&R solutions are a good fit for supermarkets in southern Europe. “The data gained from measurements and models demonstrate that the performance of integrated MultiPACK systems makes them feasible in a southern European climate,” observed thermal energy expert Michael Jokiel of project partner SINTEF in an article posted on the ‘R744.com’ website. However, as noted in the article, both the refrigeration installations and simulation models can still be improved.
The MultiPACK system is based on CO2 packs utilising ejector technology. It’s fully integrated, providing refrigeration, heating and air conditioning with CO2 as the refrigerant. “The units include parallel compression, overfed gravity evaporators, ejectors for vapor compression and liquid recirculation, and air-to-water heat pumps. The units and [sic] also include heat recovery for space heating and hot water production, and are fully instrumented for performance monitoring,” the article stated.
The 5-year MultiPACK (Demonstration of the next generation standardised integrated cooling and heating packages for commercial and public buildings based on environment-friendly carbon dioxide vapour compression cycles.) project concludes in September 2021. Its energy-efficient, plug and play units are expected to reduce the total cost of ownership and energy consumption for heating and cooling in the relevant buildings by more than 25 %.
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