Page 161 - Defrosting for Air Source Heat Pump

Frosting evenness coefficient 155

(A)

11.17 08:00 11.18 11:00 11.19 08:00 11.19 17:00 11.20 07:00

11.20 11:00 11.21 08:00 11.22 09:00 11.23 09:00 11.23 12:40
(B) (C)

frosted

Fig. 6.2 Airside surface conditions of the outdoor coil at the start of defrosting.

system performance when frost accumulates on a three-circuit outdoor coil’s surface
in an ASHP unit at different FECs has been carried out. Also, a quantitative analysis
has been conducted using the experimental data. In this section, a detailed description
of an experimental ASHP unit and the experimental conditions are first reported.
Thereafter, different experiment cases were designed and carried out, with their rel-
ative results followed. After the result analyses, the conclusions are finally given.

6.2.1 Experimental cases
6.2.1.1 Experimental setup
In this section, the experimental setup was totally the same as that previously used in
Chapter 3. So, it will be briefly introduced here. The experimental ASHP unit was
modified from a commercially available 6.5 kW heating-capacity variable-speed