Questions tagged [refrigeration]

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3answers
101 views

Relative inefficiency of doorless fridges at supermarkets

It appears to be a waste of electricity to keep a bank of refrigerators wide open with no doors or covers whatsoever on them. They seem to be just blowing cold air out into the supermarket. They ...
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0answers
16 views

Dimension of an evaporator coil

I need to cool 3 galons of water from 77 to 32°F to form an ice bank that I will use to cool beer (it is a noble effort, you see). I figured I need to install a cooling capacity of 0.34 kw to lower ...
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0answers
19 views

Evaporating temperature of NH3

Considering a flooded evaporator (using plate heat exchanger - PHE). Cold NH3 liquid from a surge drum supplies to the PHE to cool down water from 30 oC to 3 oC. The evaporating temperature of NH3 is -...
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2answers
103 views

Save money with using a refrigerator correctly - blowing cold air to the back of it?

We are heating up our houses in winter to ex.: 21C to then have an insulated box inside the house, which we cold down to 5 and -15C, and we call it a refrigerator.. :) The situation: we would buy a ...
0
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1answer
47 views

Is there any practical way to partially absorb the heat from a refrigeration condenser

I have currently been experimenting with a phase change material to absorb the heat given off by the condenser in a small refrigeration system (about 1/5 hp compressor) and while it does absorb a ...
1
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2answers
36 views

Why is the saturation pressure of the refrigerant desired to be slightly greater than atmospheric pressure in an evaporator?

I read that it "is a positive pressure against the environment". But I am not too sure what that means.
7
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5answers
3k views

Should we protect our AC's outdoor unit from sunlight?Does it increases the durability of an AC and its refrigerant if it is well shaded?

My AC outdoor unit gets direct sunlight (no shading whatsoever) from morning to noon. Temperature normally soars up to 40 degree Celsius (I am from India). I have two questions: Is this bad for the ...
3
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1answer
63 views

Store seeds at 1°C

I have prunus pits that I stratify in a refrigerator during winter. Normally, the seeds germinate in springtime, which is ideal. However, often some of the seeds germinate prematurely. When this ...
1
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2answers
116 views

How to prevent ice build up in a refrigerator?

There is ice build in my Samsung RF266 refrigerator. I have posted the following questions in Home Improvement Stack Exchange hoping to find a solution. The questions are as follows: Samsung RF266 ...
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0answers
77 views

Adjusting the pressure of the condenser and the evaporator

The picture below shows a refrigeration unit I was reading the operation manual of this unit. It is written that the pressure of the condenser is controlled by the water flow rate. Reducing water ...
1
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1answer
52 views

What will remain constant during the circulation of working substance in a refrigerating machine? [closed]

For Example, the pressure of evaporator can be changed, also the pressure of condenser and many more parameters. What is that parameter which remain constant while others keep changing ?
0
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1answer
35 views

How to compute the performance of a refrigerant?

As I understand it, there are 5 key factors that determine the performance potential of a refrigerant gas: Vapor density Enthalpy of vaporization Thermal Conductivity Critical temperature Specific ...
18
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5answers
83k views

What's wrong with transporting a refrigerator on its side?

I tried to deliver a refrigerator and the customer saw that the refrigerator was lying down in the truck instead of standing up. He refused to accept it, claiming that the compressor would be damaged ...
0
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1answer
28 views

How does Work behave in two different refrigeration setup?

Does work behave the same way for all temperature range while in a refrigeration setup. When quality of heat changes with the temperature, Does it apply to work also. IF we consider refrigerator ...
12
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1answer
2k views

Why was Freon used in spray cans before it was declared a threat to ozone?

I've heard that in the past, spray cans (aerosol cans) contained Freon. I found that the Montreal Protocol made the usage of Freon illegal due to its effect on the ozone layer, but I can't find the ...
1
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1answer
4k views

How to size a refrigeration compressor based on an evaporator size?

I purchased an evaporator holding the following specifications: Cooling Capacity = 2 kW Size = 66 X 53 X 43 What I need to know is how to choose a compressor just to gain this full cooling capacity?
1
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0answers
43 views

Efficiency of water distillation vs active Condensation Trap [closed]

I was wondering what would be more efficient means of producing clean water. The first method could be though a distillation process where by you boil contaminated water and collect the water vapor (...
1
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1answer
638 views

absorption refrigeration with low generator temperature?

I am IT engineer not a refrigeration expert, pardon my basic question. Would a NH3 or other absorption cycle work with a generator temperature of say 30C, and condenser temperature of 10C by ...
3
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2answers
650 views

What does the sand do in a pot-in-pot refrigerator?

The Wikipedia article Pot-in-pot refrigerator says that sand in the outer pot somehow affects the cooling efficiency of refrigerator. I don't understand what the sand does in this situation. For ...
9
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5answers
2k views

Difference in energy consumption between empty fridge and fridge filled with bottles of water

I have about 12 bottles of water. If I want to minimize the energy consumption of my refrigerator, should I put these bottles in the fridge or leave them out?
2
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1answer
3k views

How to find the entropy for a given temperature using P-H chart for a refrigerant?

How do I find the entropies for T1 = -10 deg C and T2 = 30 deg C, respectively using the R-134a refrigerant chart (SI):
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2answers
8k views

What does “a” mean at the end of a refrigerant's designation (R-134a)?

I was studying the designation of names to refrigerants. The following is the basic formula: R - (m - 1) ( n + 1) ( o ) where: m = number of carbon atoms in the refrigerant n = number of hydrogen ...
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2answers
191 views

Why divide the dimensions of a pressure vessel by 39.37 when calculating discharge capacity?

For a National Board Exam Review: A 29.53" * 39.37" pressure vessel contains ammonia with f = 0.041. Compute the minimum required discharge capacity of the relief device in $\mathrm{\frac{kg}{hr}}$...
1
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0answers
29 views

The Volumetric Flowrate Under Suction Condition

For a National Board Exam Review: An air conditioning plant with a capacity of $400$ $kW$ of refrigeration has an evaporating and condensing temperature of $3$ $^oC$ and $37$ $^oC$ respectively....
15
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5answers
2k views

Why don't refrigerators have parts outdoors?

I've always wondered why refrigerators don't have some of their parts located outdoors like an air conditioner. In warm weather, it seems like it would make sense to have the condenser outside like ...
2
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1answer
357 views

Thermostat design properties

Cut-in, cut-out thermostats are commonly used with refrigeration devices in order to hold a consistent temperature range. Their general operations is such that when the temperature by the probe ...