# Engineering Design

**Mass and energy balance calculations**

The system flow diagram shows the receivers (collectors), the absorption chiller, the expansion/pressurization tank (CMP TK-1), and the load exchanger (HX-1).

**IW solar thermal system flow diagram **

Preliminary mass and energy balance calculations were carried out to establish the required pipe diameter, pipe insulation thickness, and pump and valve sizing. The calculations are based on two rated operating states, the design cooling load and the design heating load, shown in Table 1. Although 50% propylene glycol in water has been selected as the working fluid for the solar collection loop, the thermodynamic properties of water have been used in the calculations due to lack of data on 50% propylene glycol under high pressure.

The operating conditions throughout the solar thermal cooling system shown in Tables 2 and 3 are calculated based on steady state mass and energy balances. The state points are those indicated in PID diagram.