Reduced load on the compressor
Application of gas-fired or waste-heat fired external cooling additional to existing refrigeration or chilling plant refrigerant circuits is called sub-cooling. Typically the additional cooling is applied to the condenser outlet stream or prior to the electrical refrigeration compressor inlet, depending upon cycle conditions. The application of additional cooling logically reduces the thermal duty of the main refrigeration circuit, and hence the electrical power consumption is reduced.
Gas versus electricity
Given a typical developed economy relationship between gas and electricity prices, FireChill gas-fired chillers providing sub-cooling will cost significantly less to operate than the offset cost of electricity to drive the main compressors, making such an installation financially attractive. It will also reduce carbon footprint.
If an installation is put in place where a CCHP plant is providing the sub-cooling from a waste heat fired FireChill set, then the operating saving is significantly higher, as is the carbon footprint reduction.
10% to 18% savings
Electricity spent on refrigeration can be as much as 40% of total energy costs in a supermarket. Independent estimates suggest a direct-fired solution could save up to 10% of total power usage in a typical store and this figure increases to 18% where a CCHP system is deployed and the FireChiller feeds off waste heat instead of gas. Savings magnitude depends entirely on the differentials between gas and electricity prices. Payback periods can be as little as two years.
Save on upgrade costs
Where a supermarket is seeking to increase marginal output capacity from its existing installation, a sub-cooling solution, which effectively delivers incremental capacity, could enable an organisation to either defer or cancel planned capital expenditure.
Carbon reduction targets
Supermarkets are leaders in sustainability and continually seeking to address their carbon footprint in line with government and CSR agendas. Sub-cooling, especially when combined with CHP, demonstrably makes a contribution to the achievement of carbon-reduction targets whilst also saving money.
