Division Definitions related to process chillers

‘rated cooling capacity’ (P_A ), expressed in kW to two decimal places, means the cooling capacity that the process chiller is able to reach, when operating at full load, and measured at standard rating conditions with the reference ambient temperature at 35 °C for air-cooled chillers and 30 °C water inlet temperature at the condenser for water-cooled chillers;

‘rated power input’ (D_A ) means the electrical power input needed by the process chiller (including the compressor, the condenser fan(s) or pumps(s), the evaporator pump(s) and possible auxiliaries) to reach the rated cooling capacity, expressed in kW to two decimal places;

‘rated energy efficiency ratio’ (EER_A ) means the rated cooling capacity, expressed in kW, divided by the rated power input, expressed in kW, expressed to two decimal places;

‘seasonal energy performance ratio’ (SEPR) is the efficiency ratio of a process chiller for providing cooling at standard rating conditions, representative of variations in load and ambient temperature throughout the year, and calculated as the ratio between annual cooling demand and annual electricity consumption, expressed to two decimal places;

‘annual cooling demand’ means the sum of each bin-specific cooling demand multiplied by the corresponding number of bin hours;

‘bin-specific cooling demand’ means the rated cooling capacity multiplied by the part load ratio, for every bin in the year, expressed in kW to two decimal places;

‘part load’ (Pc(T_j)) means the cooling load at a specific ambient temperature T_j, calculated as the full load multiplied by the part load ratio corresponding to the same ambient temperature T_j and expressed in kW at two decimal places;

‘part load ratio’ (PR(T_j)) at a specific ambient temperature T_j means:

1. (a)

   for process chillers using an air-cooled condenser, the ambient temperature T_j minus 5 °C divided by the reference ambient temperature minus 5 °C, and multiplied by 0,2 and added to 0,8. For ambient temperatures higher than the reference ambient temperature, the part load ratio shall be 1. For ambient temperatures lower than 5 °C, the part load ratio shall be 0,8;

2. (b)

   for process chillers using a water-cooled condenser, the water inlet temperature T_j minus 9 °C divided by the reference water inlet temperature (30 °C) minus 9 °C, and multiplied by 0,2 and added to 0,8. For ambient temperatures higher than the reference ambient temperature, the part load ratio shall be 1. For ambient temperatures lower than 5 °C (9 °C water inlet temperature at the condenser), the part load ratio shall be 0,8;

The part load ratio can be expressed at three decimal places or in percentage, after multiplying by 100, at one decimal place

‘annual electricity consumption’ is calculated as the sum of the ratios between each bin-specific cooling demand and the corresponding bin-specific energy efficiency ratio, multiplied by the corresponding number of bin hours;

‘ambient temperature’ means:

1. (a)

   for process chillers using an air-cooled condenser, the air dry bulb temperature, expressed in degrees Celsius

2. (b)

   for process chillers using a water-cooled condenser, the water inlet temperature at the condenser, expressed in degrees Celsius;

‘bin’ (bin_j ) means a combination of an ambient temperature T _j and bin hours h _j , as set out in Annex VIII;

‘bin hours’ (h_j ) means the hours per year at which an ambient temperature occurs for each bin, as set out in Annex VIII;

‘reference ambient temperature’ means the ambient temperature, expressed in degrees Celsius, at which the part load ratio is equal to 1. It shall be set at 35 °C. For air-cooled process chillers, the air inlet temperature to the condenser is then defined as 35 °C while for water-cooled process chillers the water inlet temperature to the condenser is defined as 30 °C;

‘bin-specific energy efficiency ratio’ (EER_j ) means the energy efficiency ratio for every bin in the year, derived from the part load, the declared cooling demand and declared energy efficiency ratio for specified bins, and calculated for other bins by linear interpolation, corrected where necessary by the degradation coefficient;

‘declared cooling demand’ means the cooling demand at a limited number of specified bins, and calculated as the rated cooling capacity multiplied by the corresponding part load ratio;

‘declared energy efficiency ratio’ means the energy efficiency ratio at a limited number of specified bins;

‘declared power input’ means the electrical power input needed by the process chiller to meet the declared cooling capacity;

‘declared cooling capacity’ means the cooling capacity delivered by the chiller to meet the declared cooling demand;

‘degradation coefficient’ (Cc) means the measure of efficiency loss due to cycling of process chillers at part load; if Cc is not determined by measurement, then the default degradation coefficient is Cc = 0,9;

‘capacity control’ means the ability of a process chiller to change its capacity by changing the volumetric flow rate of the refrigerant, to be indicated as ‘fixed’ if the process chiller cannot change its volumetric flow rate, ‘staged’ if the volumetric flow rate is changed or varied in series of not more than two steps, or ‘variable’ if the volumetric flow rate is changed or varied in series of three or more steps;