3.2. System 2: single effect absorption chiller driven by surplus
hot water
A single effect absorption chiller driven by 85.9 °C jacket water
is proposed in system 2. On the basis of the existing system, the
jacket water is divided into two parts: firstly, it is given the priority
of satisfying the heating load of the digester and then the surplus
hot water will be sent to the absorption chiller to produce chilled
water. Compared with the existing CHP system, system 2 is able to
make full use of the thermal energy of the jacket water, but the
180 °C high temperature fuel gas is not fully recovered and exhausted
to surroundings directly all year round.