Report: Reusing waste heat can save 1.3 billion m3 natural gas

According to research by Dutch firm KWA Business Consultants, annual savings from reusing waste heat produced during the refrigeration process could save industry from having to purchase some 1.3 billion cubic metres of natural gas.

The research – commissioned by the Netherlands Enterprise Agency (part of the Dutch Ministry of Economic Affairs) – found that companies could recycle up to 40% of the heat produced during the refrigeration cycle, requiring them to use less natural gas for heating.

This could help companies to meet the requirements of energy efficiency legislation, argues Paul ten Have, an adviser to KWA [CM1] . The heat reclaim process could also help businesses reduce their CO₂ emissions and fossil fuel consumption, according to the report.

Potential for supermarkets

An increasing number of supermarkets have been including heat reclaim in their CO₂ refrigeration systems. This provides heating for the building, air-conditioning and water used for cleaning.

The heat reclaim process works by using a refrigerant to carry heat given off by the compressor and other system components, which is then used as heat or energy for other parts of the store.

SCM Frigo recently delivered 10% energy savings from a ‘fully integrated’ CO₂ installation at the frozen food chain ‘Fresco & Vario’ in Conegliano (close to Treviso, Italy).

Selgros Cash & Carry, meanwhile, operates 20 stores in Romania, putting it among the top five food retailers in the market. Their Târgu Mureș store – which opened on 27 May – uses the natural refrigerant CO₂ for refrigeration, air conditioning and heating combined.

The store is fitted with a CO₂ transcritical booster rack featuring parallel compression and ejector technology. The concept also includes the first-ever CO₂ transcritical chiller for air-conditioning with overfeed flooded evaporators.

A heat recovery system delivers hot tap water and heating for the sales and office areas. This reduces the supermarket’s carbon footprint, recycling waste heat that would otherwise be emitted to the atmosphere.

“This is quite new. It’s the first such system that we’ve done for an air conditioning application,” said Marcus Hoepfl, managing director of Frigo-Consulting International Ltd., the Swiss refrigeration consulting and engineering company that carried out the installation.