ANSI/ASHRAE 23:2005 pdf download.Methods of Testing for Rating Positive Displacement Refrigerant Compressors and Condensing Units.
dew-point tenrperature: a vapor-liquid equilibrium point fora volatile pure liquid or for a multi-component mixture ofmiscible. volatile pure components. in the absence of noncondensables. where the temperature of the mixture at a defined pressure is the maximum temperature required for a liquid drop to form in the vapor.
energy eJficienc’ ratio (EE$): a dimensional ratio of the cooling capacity (Btuih) to the power input (W).
enthalpy: thermodynamic parameter equal to the sum of the internal energy of a system and the product of its pressure and volume at the same thermodynamic condition (compare to
•cpt’cific enthalpv).
error: the diflerence between the true value of the quantity measured and the observed value. All errors in experimental data can be classified as one of Iwo types: systematic (fixed) errors or random (precision) errors. The terms accuicv and precision are oflen used to distinguish between svswmasic and random errors. A measurement with small systematic errors is said to be unbiased. A measurement with small random errors is said to have high precision. A measurement that is unbiased and precise is said to be accurate.
fixed error: a term that has the same meaning as systematic error
flowmever: a device employing a detecting element that determines the flow rate of a volatile refrigerant in the gaseous or liquid phase within a closed conduit by measuring a suitable response of the detecting element.
fractionation: a change in composition of a refrigerant blend by preferential evaporation of the more volatile component(s) or condensation of the less volatile component(s).
glide: the difference between the deu-pnini’ lemperurure and the bubble-point temperature at a constant pressure.
hermetic compressor: a motor-compressor assembly contained within a gas-tight housing that is permanently sealed by welding or brazing with no access for servicing internal parts in the field.
liquid refrigerant injection: a method of internally cooling the compressor mechanism or oil, or the reduction of discharge temperature by introducing saturated or subcooled discharge-side liquid refrigerant into the compressor or condensing unit. Liquid refrigerant injection mass flow rate is not taken into account when calculating compressor or condensing unit efficiency, capacity, or volumetric efficiency.
nsotor-compressor: a motor and an open compressor mounted onto a common base but not integrated into a gas-tight housing (compare to sen,i-hermetic compressor).
near-azeotropic: a zeotropic refrigerant blend with a temperature glide sufficiently small that it may be disregarded without consequential error in analysis for a given application.
oil circulation rave: the ratio of the mass of oil circulating through a refrigerant system to the total mass of refrigerant and oil flowing through the system at a specified set of operating conditions.
open compressor: a refrigerant compressor with a shaft or other moving part extending through its casing to be driven by an external source of power.
performance factor: the ratio of capacity to power input at speelfied operating conditions. Using consistent units, the performance factor may be expressed in dimensionless form as a coefficient of performance (COP) or as the enerv cliiWfl(v ratio (EER).
positive displacement refrigerant compressor: a machine that increases the pressure of a refrigerant vapor by reducing the compression chamber volume.
power input: a term used to refer to the power input to the shaft of open compressors: the power input at the motor terminals for hermetic compressors, semi-hermetic compressors, or motor-compressors: or to refer to the power absorbed by all ancillaries that are necessary to sustain the operation of the compressor or condensing unit (e.g.. oil pump. fan motors. controls components. and circulating pumps).
precision error: a term that has the same meaning as random error
primary test: a test performed to determine the ratings of a compressor or condensing unit (compare to confirming test).
random error: an error that causes readings to take random values on either side of a mean value. The random error is quantified based on how well an instrument can reproduce subsequent readings for an unchanging input. Random errors cannot be corrected through calibration.
refrigerant blend (or mLrture): a refrigerant composed of two or more different chemical compounds, compounds that arc often used individually as refrigerants for other applications.
