Page 324 - Defrosting for Air Source Heat Pump
P. 324

Technoeconomic performances                                       319


                     28,000
                                       Heating season with frost formation
                     26,000            Heating season without frost formation
                                       Cooling season
                     24,000
                    (h)
                    n  22,000
                    o
                    i                                         168.75
                    t
                    a
                    r              21,459.38                   0.79%
                    u  20,000
                    d
                    g
                    n  18,000
                    i
                    t
                    a
                    r
                    e
                    p  16,000
                    o               16,200
                    m
                    e  14,000
                    t
                    s
                    y
                    S  12,000
                     10,000         10,800
                      8000
                                   Case D3               Case D4
                                           Two typical cases
           Fig. 10.8 System operating durations in three seasons in the 15 operating years.
                     80,000
                                       Heating season without frost formation
                                       Indoor thermal consumption on defrosting
                     70,000
                                       Electricity cost on defrosting
                                       Electricity cost on frosting
                     60,000
                                    53,917.29
                    )                               48,589.22
                    Y  50,000
                    N
                    C                22,404.26
                    (
                    t  40,000        41.55%          20,692.1
                    s
                    o
                    c                                42.59%
                    g         )
                    n  30,000  %
                    i
                    n         5
                    u         4
                    R         .  8
                     20,000   5  (
                              3                                   27,897.12 (57.41%)
                              0
                              .     28,893.29        26,035.71
                     10,000   3  1
                              5     53.59%           53.58%
                              ,
                              1
                              3
                         0
                                     Case D3         Case D4
                                           Two typical cases
           Fig. 10.9 Running costs in two heating seasons in the 15 operating years.
              In heating season with frost formation, the running cost difference between the two
           cases is $542.17. That means that after the valves were installed on the ASHP unit, the
           total running cost in this season could save about 11.47%. The economic performance
           of the new ASHP unit was effectively improved. In heating season without frost for-
           mation, the total running cost difference between the two cases became $256.72,
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