Page 352 - Defrosting for Air Source Heat Pump

348 Appendices

Appendix B: Calculation error of defrosting efficiency

The calculation error of defrosting efficiency can be obtained by
q ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
2 2
2 2
2 2
δ y ¼ a δ + a δ + a δ (B.1)
1 1 2 2 3 3
4
in which δ 1 and δ 2 are the measurement errors of frost mass, m f and m v ,at10 . δ 3
2
is the measurement error of energy consumption, at 10 . The other three parameters,
a 1 , a 2 , and a 3 , could be calculated by,
∂η d L sf
a 1 ¼ ¼ (B.2)
∂m 1 Q e
∂η d L v
a 2 ¼ ¼ (B.3)
∂m 2 Q e
∂η d L sf m 1 + L v m 2
a 3 ¼ ¼ 2 (B.4)
∂Q e Q
e
Finally, the calculation error of defrosting efficiency was calculated at 0.15%.