Questions tagged [refrigeration]

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1answer
32 views

Replacing R22 with R12 for same load, same compressor possible? [closed]

This is from GATE 1992 My answer - can, higher Book answer - cannot, higher Sometimes this book tends to have some mistakes. I tried finding solution all over internet. All I got is "cannot, ...
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2answers
66 views

Cooling system to maintain 0.5 °C at 95% humidity

I am looking for some guidance on a redneck cooling system. I need to store seeding trees at a temperature just above freezing, and at a humidity of close to saturation. I only need the system for ...
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1answer
58 views

Identify this textbook

I would really like to buy this textbook, but only see a scan of one chapter online. Could anybody help me identify the book? Thanks!
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1answer
113 views

Dehumidification calculations

I'm looking at options for DIY dehumidification and am hoping to get a sanity check on some calculations, and verification that I'm using the right factors in the right way. As a reference point, I ...
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2answers
61 views

Why are there no propane refrigerator air-conditioning units that run on solar heat?

I was thinking about how hot it was outside, when a thought came to me. There are propane refrigerators, so why not replace the propane as the heat source with solar heat and then change it from a ...
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2answers
65 views

Copper pipe for brine water block ice system

I am looking to replace copper pipes from a brine water block ice system . The pipes needed are 5/8 but wonder what wall thickness it should be. They should be thick enought to withstand 60 psi ...
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2answers
61 views

Can Peltier Modules be used as an Air Conditioner? [duplicate]

Air Conditioners are very expensive so I'm planning to build a split type air conditioner using Peltier modules for my sealed room that is 6.5 length, 7 feet height, and 5.6 wide. I plan to use nine ...
4
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0answers
35 views

Why is there limited use of Y (Wye) fittings in a refrigeration system?

I'm a Mechanical Engineering intern currently working in HVAC and Refrigeration for grocery stores. I'm looking into ways, with lower energy losses, to encourage equal flow distribution at liquid pipe ...
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0answers
26 views

Where to connect the tubes on the refrigerator compressor to operate by using hand?

I am trying to operate the compressor of a refrigerator using my hand. I have opened the case of the refrigerator compressor and removed the part responsible for the compression. I have made a gearbox ...
2
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2answers
65 views

How to increase temperature of the condenser part in a refrigeration cycle?

I have made a refrigeration system at my home. I am using r134a as the refrigerant. I want to achieve a temperature of about 70-degree Celcius in the condenser part and 0-degree Celcius in the ...
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0answers
34 views

What if ammonia is used as a refrigerant for a refrigerator?

I have a refrigerator whose compressor configuration is: power- 10hp compression ratio- 10:1 I do not have expertise in this field, but I am curious if I use ammonia as a refrigerant instead of HFC-...
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1answer
56 views

How is heat transfer calculated for an aqueous salt solution?

I am familiar with using $\dot{Q}=c_p\cdot\dot{m}\cdot\Delta T$ to calculate the heat transfer rate of a fluid given a singular value for specific heat capacity (such as with water), but how do I go ...
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2answers
122 views

Why aircraft refrigeration uses a centrifugal compressor in place of reciprocating compressor?

Why aircraft refrigeration uses a centrifugal compressor in place of reciprocating compressor and a gas turbine in place of reciprocating expander?
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2answers
58 views

RV HVAC and Fridge Freezer on the same coolant loop?

Given the space, weight, and power constraints of an RV it is useful to make as much use as possible out of every component. Is there an engineering reason why a refrigerator / freezer and an air ...
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1answer
23 views

Has anyone built a heat powered vapor compression cooler?

I've had this idea in my head for a refrigeration cycle which is powered by heat, uses only one fluid, and whose only moving part is the fluid. I would like to know if my idea is new, or if it's ...
2
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1answer
7k views

Can Peltier Modules be practically used to cool a room?

I am thinking of building a indirect Peltier AC to cool a room of approx size 30m3. Single/multiple peltier modules will be used to cool a insulated box with water inside. The box will be kept outside ...
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0answers
33 views

Can any Air rotameter be used for refrigerant gas by using equation conversion?

Currently, I am trying to find rotameter calibrated for R134A gas flow. However, most companies only sell rotameter or variable area flowmeter for water/Air/Nitrogen flow. Is it possible to use any ...
4
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2answers
618 views

Can a Peltier's device (i.e.Thermoelectric cooler) achieve cryogenic temperature efficiently?

Does the stacking of peltiers device shows promising results in achieving the cryogenic temperature? I have tried doing the experiment, the overall temperature of the system increased around 80ºC and ...
2
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1answer
232 views

Modelling a refrigeration cycle in Excel

Is it possible to model a heat pump cycle without using tools like EES, but using Excel? I am considering to use Refprop application as an add-in in Excel, and model a heat pump cycle. Another ...
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0answers
31 views

DC Inverter motor AC utilization category

I am looking at specs of an air conditioner unit. It uses DC inverter technology and maximum current listed as 21.5A So are DC inverter motors considered resistive or inductive? What utilization ...
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2answers
61 views

What is the idea behind an expansion valve?

I am watching this video(https://www.youtube.com/watch?v=gVLhrLTF878) and beginning at around the 2:20 mark, it explains the significance of an expansion valve with the following ideas: Restricts ...
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3answers
172 views

1 Ton of Refrigeration

"1 TR is equivalent to the rate of heat transfer needed to produce 1 U.S. ton (2000 lbs) of ice at 32F from water at 32F in one day, i.e., 24 hours." While defining 1 Ton of Refrigeration (TR), why ...
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3answers
498 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
75 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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2answers
144 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 ...
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1answer
56 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 ...
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2answers
156 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.
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5answers
25k 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
80 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 ...
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2answers
695 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
120 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 ...
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1answer
57 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 ?
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1answer
40 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 ...
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6answers
212k 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 ...
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1answer
33 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 ...
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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 ...
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1answer
7k 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?
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0answers
53 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 (...
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1answer
916 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 ...
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2answers
901 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 ...
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5answers
3k 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?
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1answer
6k 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
16k 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
280 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 $\mathrm{\frac{kg}{hr}}$...
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0answers
30 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....
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6answers
5k 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 ...
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1answer
418 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 ...