“…The mean of the unaccounted for heat losses from the rest of the system was 11.35 per cent with a standard deviation of 1.387 per cent. Experimental heat pump system 2 was designed after experience with the above unit and with specially designed research heat pumps (El Meniawy, Watson and Holland, 1980Holland, , 1981 ; Gutierrez et al, 1979). The results of 29 experimental runs, using R l l as the working fluid, are shown in Figure 10 together with the 'best fit' curve representing the data.…”