Functional Design of the mCCHP-RES System - Design for Micro-Combined Cooling, Heating and Power Systems - page 257

- Ef ciency g ST [%],

- Nominal flow rate [l/h],

- Maximum operation pressure [bar].

The required characteristic which is imposed by the system functioning, and
based on which the component is chosen from the market and is embedded into the
system, is the absorber area (A ST ) of the ST panel. To size the solar thermal panel,
the absorber area should be determined by the following steps:

(a) Determining the amount of energy produced by the ST panel, Q ST max , in the
month in which the ST panel production is the biggest:

Q ST max ¼ A TFA q ST max ð KWh = month Þ ð 16 Þ

(b) Determining the produced energy in a day of this month, Q ST day :

Q ST max
k N days

= ð Þ

Q ST day ¼ ½ kWh d 17

ow Q day can be calculated with the following relation. Their
obtaining value will be used for choosing the circulation pump.

(c) The heat

Q STday
t sunlight

Q day ¼

½ kW ð 18 Þ

where:
A TFA floor area of residence [m 2 ]; total

q ST max value of speci c heat production in the month with the biggest production

of the ST panel [kWh/m 2 ];

N days number of days of the month;

k reduction factor which account for cloudy days of the month (typically

2 - 3 days). This factor belongs to the interval (0.7 - 0.9).

t sunlight represents the medium sunshine time at the nominal thermal power of the

solar thermal panels corresponding to a 1,000 W/m 2

6hin
medium depending on the climatic in which the building is situated).

radiation (4 -

(d) Determining the absorber area (A ST ), with the following formula:

m 2

Q ST day
H

A ST ¼ ð 19 Þ

where:
H is the solar daily irradiation (kWh/m 2 ).