Structural Design of the mCCHP-RES System - Design for Micro-Combined Cooling, Heating and Power Systems - page 146

Heating season Heating season

External temperature

θ isetpoint

Internal temperature

20

15

θ b Base tempera-

10

average external temperature
during heating season

5

θ e

0

Jan Feb Mar Apr Ma Jun Jul Aug Sep Oct Nov Dec

0 50 100 15 200 250 300 350

Days of the year

Fig. 4 Determination of seasonal climate by use of monthly average data

P 36 1 # e ; i
d hs

# e ; hs ¼ for # e ; i # b ð 2 Þ

# i is the interior temperature (setpoint internal temperature for space heating). Its

standard value is

20 C

# i ¼

Solar radiation is the radiant energy received from the Sun. It is the intensity of
sunrays falling per time unit and per area unit, and is usually expressed in Watts per
square meter (W/m 2 ). The radiation incident on a surface varies from moment to
moment depending on its geographic location (latitude and longitude of the place),
orientation, season, time of day, and atmospheric conditions. Solar radiation is the
most important weather variable that determines whether a place experiences high
temperatures or is predominantly cold. The instruments used for measuring of solar
radiation are the pyranometer and the pyrheliometer. The duration of sunshine is
measured using a sunshine recorder.
The solar irradiation H solar during the heating season is given by equation:

P i H solar ; i
d hs

H solar ¼ for # e ; i # b ð 3 Þ

where:
H solar ; i is daily solar irradiation on 1 m 2 surface in heating season