ZEMCH 2015 - International Conference Proceedings | Page 688

Solar collector field _NANOFLUID:
• Tested flow rate = 0.02 kg/s*m2;
• Intercept efficiency = 0.553;
• Efficiency slope = 2.053 W/m2*K.
Hot water buffer storage (Type 60).
• Tank volume = 2.5 m3;
• Tank loss coefficient = 2.5 kJ/hr*m3 *K.
External backup heater (Type 6).
The heater is designed to add heat to the flowstream at a user-designated rate (Qmax) whenever
the external control input is equal to one and the heater outlet temperature is less than a specified maximum (Tset).
• Maximum heating rate = 25 kW, it will be the product of the maximum possible energy transfer
and the conversion efficiency;
• The thermal conversion efficiency = 0.79 (natural gas);
• Set temperature of heater internal thermostat, which ensures proper operation of the generator = 85 °C.
Hot Water-Fired Single-Effect Absorption chiller (Type 107).
The amount of energy to remove from the chilled water stream in order to bring it to the set point
temperature is calculated by the following equation:
(2)
The required energy removal is then divided by the machine’s capacity to determine the fraction
of design load at which the machine is required to operate.
(3)

The capacity of the machine at any given time, therefore:
(4)
The energy delivered to the chiller by the hot water stream can be calculated using the following
equation:
(5)

The hot water stream outlet temperature is then:
(6)

The chilled water outlet temperature, which should be the set point temperature, but may be
greater if the machine capacity is limited, is then calculated as:
(7)

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ZEMCH 2015 | International Conference | Bari - Lecce, Italy