PDF Publication Title:
Text from PDF Page: 055
1.75 1.50 1.25 1.00 0.75 0.50 0.25 0.00 Heating Load Cooling Load -30 -20 -10 -0 10 20 30 40 50 Outdoor Temperature (C) Figure 5.2 Capacity normalization as function of heating capacity and outdoor temperature The load is approximated as a linear function of temperature with a balance point of 18.3oC. While the actual load for a given outdoor temperature may vary considerably depending on a variety of factors (solar loads, wind speed, etc.), for an annualized approximation the linear load approximation is reasonable. The heating load is normalized as a function of the outdoor temperature at which 1 kW heating capacity is required, as shown in Figure 5.2. The three lines shown for heating loads correspond to various levels of insulation. The cooling load is normalized based on a 1 kW load requirement at 45oC. Since solar radiation and infiltration of hot humid air dominate cooling loads, only one line is shown. Between an outdoor temperature of 18.3oC and 26.6oC it is assumed that ventilation can meet the cooling load. 5.2 Cycle assumptions o It is assumed that the airflow rate over the outdoor coil is 0.15 kg/s per kW cooling capacity at 45 C outdoors. This airflow rate was shown in Figure 5.22 to provide the maximum efficiency in cooling for R410A and is comparable to systems currently available. As a result, it is a reasonable basis of comparison for the two systems. In heating, the evaporating temperature is determined based on the assumption that the air and refrigerant exit temperatures in the outdoor coil are pinched. In heating mode the return air temperature is assumed to be 21oC, and supply air temperatures of 40 and 60oC are considered. In cooling mode, an evaporating temperature of 12oC is assumed for all conditions to provide sufficient dehumidification. The compressor is sized such that the 1 kW load at 45oC is met. It is assumed that a variable displacement compressor is used, that the efficiencies are equal to those given in Chapter 4 (Equations 4.1 and 4.2), and that the isentropic and volumetric efficiencies are constant from maximum displacement to one-third maximum capacity. Below one-third of maximum capacity, both systems are assumed to cycle at maximum efficiency to meet the load; 44 Capacity (kW)PDF Image | Comparison of R744 and R410A
PDF Search Title:
Comparison of R744 and R410AOriginal File Name Searched:
CR039.pdfDIY PDF Search: Google It | Yahoo | Bing
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
Heat Pumps CO2 ORC Heat Pump System Platform More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)