Journal of Energy in Southern Africa • Vol 19 No 4 • November 2008
Energy from the exhaust gas of an internal combus-
tion engine is used to power an absorption refriger-
ation system to air-condition an ordinary passenger
car. The theoretical design is verified by a unit that
is tested under both laboratory and road-test condi-
tions. For the latter, the unit is installed in a Nissan
1400 truck and the results indicate a successful pro-
totype and encouraging prospects for future devel-
Keywords: car air-conditioning, absorption refriger-
ation, renewable energy
Since 1987 the Montreal Protocol controls the use
and release of CFCs and has set a time-scale sched-
ule for eliminating their production. This agreement
is an historic step in the ongoing process of building
consensus regarding environmental impacts of
CFCs (Epstein and Manwell, 1992).
One of the HCFCs, R-22, and one of the HFCs,
R-134a, are utilised as substitutes for CFCs, but the
HCFCs and HFCs will face similar restriction for
their high GWP 9 the parameter of Global Warming
Potential). For comparison, some of the working flu-
ids’ ODP (the parameter of Ozone Depletion
Potential ) and GWP are listed in Table 1 (Epstein
and Manwell, 1992).
To date, almost all car air-conditioning systems
are charged with R-134a. However, alternatives
with lower GWP than R-134a are desirable.
Some new systems are being developed in order
to revitalise the use of ecologically safe refrigerants.
For example, a system for car air-conditioning using
CO2 as the refrigerant has been developed by
Lorentzen and Pettersen (1993). The testing of a
laboratory prototype has shown that CO2
acceptable refrigerant for car air-conditioners.
Due to the international attempt to find alterna-
tive energies, absorption refrigeration has become a
prime system for many cooling applications. Where
thermal energy is available the absorption refrigera-
tor can very well substitute the vapour compression
Table 1: Environmental impact