4 cfm per square foot area for infrequent and 9 for average use. Introduction in industrial refrigerated facilities such as cold or freezing rooms, where doors need to remain open even for short periods during access operations, the air infiltration can represent more than half of the refrigeration load [1]. The infiltration rate is the volumetric flow rate of outside air into a building, typically in cubic feet per minute (cfm) or liters per second (lps) The air exchange rate, (i), is the number of interior volume air changes that occur per hour, and has units of 1/h. Infiltration load, which is due to surrounding warm air entering the refrigerated space through the cracks and open doors Product load, which is the heat removed from the food products as they are cooled to refrigeration temperature
Internal load which is heat generated by the lights, electric motors, and people in the refrigerated space 50fpm x door opening area x no Of door openings over the working period x duration for which door is opened each time (in minutes) So you get total volume of infiltration Distribute it over the working period and you will get volume flow rate You know the conditions of ambient air and conditioned
This may then be factored by the room volume and the heat removed in cooling outside air to storage conditions in btu/ cu ft as tabulated in table 5 to obtain the infiltration load. (4) infiltration air load, which is heat gain associated with air entering the refrigerated space The first four segments of load constitute the net heat load for which a refrigeration system is to be provided The fifth segment consists of all heat gains created by the refrigerating equipment Thus, net heat load plus equipment heat load is the total refrigera. Estimates the refrigeration load due to infiltration through a doorway due to temperature effects only
Disclaimer of warranties and limitation of liabilities These files were prepared by the irc Neither the irc, nor any person acting on behalf of them Makes any warranty or representation whatsoever, express, or implied, with respect to the use of any information, apparatus, method, process. This document discusses the calculation of refrigeration load, which includes transmission load through walls/roof/floor, product load from cooling/freezing products, internal load from equipment like lights/motors, infiltration load from open doors, and equipment load from devices like fan motors and defrosting It provides examples of calculating each type of load, such as transmission load.
(1) the heat transmission through the roof, floor, and walls (2) infiltration through open doorways (3) internal loads from lights, people, motors, and lift trucks (4) defrost heat and (5) the product load cooling, freezing, and maintaining the temperature of products. H = heat loss expressed in btu’s per hour The maximum refrigeration load is during loading and pull down to 150c for 1000 bags/day per chamber of potatoes each bag weighing 50 kg thus totaling to 50 tons/day per chamber (4% of 1250 tons) and the cooling load indicated is 85.32 kw (24.37 tr) per chamber. Air infiltration flow through doors represents the major fraction of the thermal load in a refrigerated aera Therefore, its evaluation is of utmost importance for an adequate sizing of the refrigeration system The existing expressions in the literature of the air flow rate through doors are adapted to a standard configuration which considers stationary regimes
OPEN
