Decentralized Poly-generation of Energy: Basic Concepts - Design for Micro-Combined Cooling, Heating and Power Systems - page 56

Or

!

Q F

PES ¼ 1 100

E sys Q sys

g Href g Eref þ

where:

C
COP ref

E sys ¼ E þ

ned
in cogeneration, when the cooling energy is generated through electric energy
consumption. Generalizing to thermal systems (activated thermally), where cooling
energy is generated through thermal energy consumption, we may de

Under this form, the relation is similar to the relation for calculating PES de

ne PES with

the similar cogeneration relation:

0
@

1
A

Q F

PES ¼ 1 100 ð 18 Þ

% C

COP ref
g Href

Q H þ

E
g Eref þ

or

!

Q F

PES ¼ 1 100

%

E sys Q sys

g Href g Eref þ

where:

C
COP ref

Q sys ¼ Q H þ

3.2.2 Energy Ef ciency of the Trigeneration Systems

PES refers basically to the percentage of fuel saved from the energy production of
the CCHP system compared to the same energy produced separately. PES does not
point if this production of the CCHP system is useful or not. Energy can be
exceedingly produced and dissipated in the environment (especially for thermal
energy). The second indicator sets the correlation between the produced and useful
energy. This is also called CCHP ef ciency. The second performance indicator is

CCHP system ef ciency given by relation: