Heat Loads/calculations Flashcards
(25 cards)
TD and relative humidity numbers
5-8f = 90%+ RH
10f = 80-90% RH
15f = 70-80% RH
20f = 50-70% RH
4 main load calculations once survey is complete
Transmission load
Air change load
Miscellaneous load
Product load
What is transmission load ?
Heat gain that is directly proportional to to the temp difference between the two sides of the wall.
What is air change load, or infiltration load ?
What is the K factor ?
Insulating value of any material as rated by its thermal conductivity
What is the U factor
Overall co-efficient of heat transfer
What is the R factor ?
Thermal resistances
What is X represented as for the k factors
Inches of insulation
What is the principle problem to do with food storage ?
Main a reasonably low, constant temperature
For frozen storage what temperature is best for all around use ?
-5f
What is meant by cool storage ?
Storing foods at temperatures above freezing
What is meant by cool storage ?
Storing foods at temperatures above freezing
The speed which fats oxidize depends largely on what ?
Nature of fats, and temperature of storage
The lower the temp the ….
Lower the oxidation
It is literally true that carrot in the sun for ….
2 hours will lose more vitamin A content then one packed in fine ice for a week
What happens if vegetables are packed in tightly sealed plastic bags ?
They will suffocate
Can’t exchange oxygen and CO2 with the atmosphere
Why in commercial quick freezing, foods are frozen as soon as possible after harvesting ?
Retains appearance and vitamin content.
Some products must be frozen 1 hour after harvesting
What is blanching ?
Pre heating the vegetable until the inside reaches 190f
At what temperature and how long should you freeze pork to kill any eggs, larva or adult worms ?
0f for at least 3 days
What temperature is quite satisfactory for most frozen foods ?
Storage temp of -5f
How should relative humidity be kept high during frozen storage ?
Using large evaporators and keep to a minimum the temperature difference between the evaporator and frozen product
Processing high acid foods at temperature of what ? Will destroy yeast and mold
212f for the appropriate length of time
In order to destroy bacteria spores in a short time what temp must the food be processed at ?
240f
What causes food spoilage ?
Enzyme action and growth of microorganisms
