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CSA C748-13 pdf free download

CSA C748-13 pdf free download.Performance of direct-expansion ( DX ) ground-source heat pumps.
equipment at the desired wet- and dry-bulb temperatures. Suitable means for measuring the wet- and dry-bulb temperatures of the air entering and leaving the equipment and the external resistance should be provided.
F.7.3 Loop air-enthalpy method (see Figure F.2)
This arrangement differs from the tunnel arrangement in that the air measuring device discharge is connected to suitable reconditioning apparatus which is, in turn, connected to the equipment inlet. The resulting test loop” should be sealed so that air leakage at places that would influence capacity measurements does not exceed 1.0% of the test airflow rate. The dry-bulb temperature of the air surrounding the equipment should be maintained within ±3.0 °C (5.4°F) of the desired test inlet dry-bulb temperature. Wet- and dry-bulb temperatures and external resistance should be measured by suitable means.
F.7.4 Enclosure air-enthalpy method (see Figure F.3)
In this arrangement, an enclosure is placed over the equipment under test, or the applicable part of the equipment. This enclosure may be constructed of any suitable material, but should be non-hydroscopic, airtight, and preferably insulated. It should be large enough to permit inlet air to circulate freely between the equipment and the enclosures, and in no case should the enclosure be closer than 15 cm (6 in) to any part of the equipment. The inlet to the enclosure should be remotely located from the equipment inlet so as to cause circulation throughout the entire enclosed space. An air measuring device is to be connected to the equipment discharge. This device should be well insulated where it passes through the enclosed space. Wet- and dry-bulb temperatures of the air entering the equipment are to be measured at the enclosure inlet. Temperature and external resistance measurements are to be made by suitable means.
F.7.5 Room air-enthalpy method (see Figure F.4)
In this arrangement, the equipment to be tested is typically located in the test rooms. An air-measuring device is to be attached to the equipment indoor air discharge, then, in turn, connected to suitable reconditioning equipment. The discharge air from the reconditioning apparatus provides the desired wet- and dry-bulb temperatures where air-sampling devices and manometers can measure wet- and dry-bulb temperatures and external resistance, as required.
F.7.6 General
The arrangements shown in Figures F.1, F.2, F.3, and F.4 are intended to illustrate various possibilities available and should not be construed as applying specifically or solely to the types of equipment with which they are shown. However, an enclosure as shown in Figure F.3 should be used when the compressor is in the indoor section and separately ventilated.
F. 7,7 Alternatives
Other means of handling the air leaving the airflow measuring device and supplying air at the proper conditions to the equipment inlet may be employed provided that they do not interfere with the external resistance measurements or create abnormal conditions surrounding the equipment.CSA C748-13 pdf free download.

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