After considering these heat losses, the energy rate on the front glass of LCPV module, [[??].sub.g], can be expressed as
The incoming energy rate to LCPV module, [[??].sub.in], is given as
where [tau] represents transmission coefficient of front glass of LCPV module.
The output energy rate of LCPV module, [[??].sub.out], is calculated using the following expression :
The energy efficiency of LCPV system can be defined as the ratio of output energy rate to the input energy rate.
Similar expression for output exergy rate of LCPV system is given as 
where [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] which includes electrical exergy destruction rate ([[??]x.sub.des,el]) caused by series and shunt resistance losses , optical exergy destruction rate ([[??]x.sub.des,opt]) caused by optical losses in LCPV module surface [17, 18], thermal exergy destruction rate[MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]caused by temperature difference between LCPV module surface and the sun surface temperature , and thermal exergy destruction rate [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] caused by temperature variation of LCPV module with respect to reference environmental state [19, 20].
In case of LCPV/T systems, thermal losses become thermal gain, which is not in the scope of this paper (which deals with only electrical energy and exergy analysis of LCPV system).
where the first term represents electrical exergy rate ([V.sub.mp] and [I.sub.mp] being a voltage and current, resp., at maximum power point of LCPV module) and the second term represents thermal exergy rate due to the temperature difference between cell temperature and ambient temperature.
The exergy efficiency of LCPV system is defined as ratio of output exergy rate to the input exergy rate of the system :
The maximum power output of LCPV module is related to the [I.sub.SC] and [V.sub.OC] by following:
The electrical power conversion efficiency ([eta]) of LCPV module can be calculated by the ratio of maximum output power generated by LCPV module to the input power carried by solar radiation (i.e., [eta] = [P.sub.MAX]/[lambda]).