What are the guidelines to design of a cold room?

Answer 1

You should have some assumptions:

1- Capacity of the room: the volume of space required.

2- Chilling capacity: the volume and average specific thermal coefficient of the goods you are storing in the room.

3- Chilling period: How long do the goods stay in the room?

4- Access frequency: How many times a day will the room be accessed?

5- Ambient temperature: The average winter / summer ambient temperature of the outer space. both immediate (indoor access) and secondary (out of building)

You should calculate the following thermal loss values:

1- Thermal value of the room space to be cooled.

2- Thermal value of the goods to reach the nominal temperature.

3- Volume of air in circulation when the access door is opened.

4- Thermal flow of the walls, doors and glass windows. each separately.

5- Using the chilling period, you should calculate the ultimate minimum temperature, during which the goods can reach the nominal required temperature (e.g. when you chill a meat lump, the inner part takes a longer time to freeze and chill down in minus 15 room temp. compared to a room temp minus 30. However this time measurement is not linear).

6- When calculating wall thermal loss, you may be permitted to choose the wall thickness. In such case, you should make a model comparison with different wall thicknesses to find most economic chilling power.

7- The chilling power is therefore calculated by summing up the thermal value of said parameters. Usually you will find it more convenient to write several scenarios to reach an optimal calculation.