Using renewable energy to achieve thermal efficiencies of up to
145 percent in commercial buildings Condensing gas-fired
hydronic boilers have become increasingly popular in commercial
heating applications during the last 20 years. Several models of
condensing boilers now have thermal efficiencies approaching 100
percent at low firing rates and return-water temperatures.
However, the 100-percent level remains the fundamental
efficiency limit for hydronic heating systems in the commercial-
buildings sector. Gas-fired absorption heat pumps can be used in
commercial heating applications and achieve thermal-efficiency
levels as high as 145 percent by drawing heat from renewable
energy resources, such as the ground, water, or ambient air.
Absorption heat pumps use natural ammonia-water refrigerant and
offer energy and carbon-dioxide- (CO2-) emissions savings of up
to 30 percent or more, compared with condensing boilers.
Absorption heat pumps have gained significant market share in
Europe and recently were introduce