Refrigerant Definition and 36 Threads

Hi everyone, I'm fairly new to HVACR systems and currently doing research on building an estimation model of a basic vapor compression cycle. Right now, I'm trying to calculate the enthalpy change across the compressor — from point H1 (before the compressor) to point H2 (after the...

To get water into a pressurised steam engine boiler, an injector passes high pressure steam through a converging/diverging nozzle, sucking cold water in at the throat. The resulting steam/water mix is at a higher pressure, but lower temperature, and so is able to return to the boiler. Heat is...

Hi there, I went to a learning visit to a small plant where it was intended to use a refrigerant cycle to cool down water used in a heat exchanger; from what I've gathered they had to stop using the refrigerant unit altogether as they're doing little batch productions per day, resulting in...

How much energy is used to compress e.g. 0.8 Kg (typical mass in a typical fridge freezer; edit: I've just seen that 0.8 kg is not normal at all; it's more like 150 g - this means my idea should be quite cheap and compete well with rechareable batteries) R134A refrigerant and could it be...

Hey everyone. Bit of a random question. So when refrigerant has been fully condensed I understand that it's a liquid, just like a glass of water, albeit under pressure and with no gas above it. When the refrigerant has been superheated it's just a gas, like you would get if you took a sealed...

I am trying to reconcile HFC-134a refrigerant with the 2nd Law of Thermodynamics. I shouldn't be able to extract useful work from a single temperature reservoir. Suppose I use a refrigeration / heat pump cycle with HFC-134a as shown below. -Compressor adds 29 kJ/kg increasing refrigerant...

I was just wondering if a mini fridge could ever work on electricity alone with no toxic chemicals inside?

When I was looking at the list of related threads to my thread "How does metering device in an A/C cause flash gas", I noticed an interesting thread titled "How does low charge on an A/C cause the subcooling to be low". PeterDonis and fourthindiana had an interesting conversation on that...

A water cooled plate condenser, condensing refrigerant. Heat exchanger (condenser with plates) characteristics: Description symbol value value (converted) number of plates np 28 number of channels nc 27 number of water channels nwc 14 number of flowing channels for refrigerant...

This is a past exam Q, I don't have the attached pressure enthalpy diagram. Q = 120kW Cp = Refrigerant enthalpy = I've looked this up, for ammonia enthalpy = 35.06 kJ / mol T2 = 5 degrees C = (5 deg C) (1100 kPa/300 kPa) = 18.33 deg C +273.15 K = 291.48 K T1 = 2 degrees C = (2 deg C)(1100...

On Friday I worked on a straight air-conditioner (A/C) package unit on the roof of an industrial facility. The straight A/C uses R-22 refrigerant. The straight A/C has a fixed orifice metering device. The compressor of the straight A/C was cold and had condensation on it. The dataplate for...

As many refrigerants are being replaced due to environmental concerns, it seems to me that isoprene could be safe and inexpensive but has not been used. Am I missing something? Its higher boiling point can be compensated by working slightly below atmospheric pressure.

WHERE is the refrigerant stored in the refrigeration system when the system is in OFF and in WHAT state Gas or Liquid ?

How about using air inside the freezer as a refrigerant instead of some refrigerant gas ( such as Freon/Ammonia.). We can Compress the air inside the freezer in the compressor, loose the heat and leave the thus cooled air back in the freezer. ; and the cycle continues. What are the problems...

When a refrigerant crosses a heat exchanger device or has some heat added into it, like condenser/evaporator or boiler/cooling tower, does the phase always change? If that's so, why? Or do we need to check if the temperature is above or under the boiling point?

hi，all. I want to calculate thermodynamic properties of refrigerant R410B. I get some data from www.eThermo.us Can anyone tell me if the accuracy of this website is OK? I use these data for my heat exchanger design. Thank you! Ning

I think this is a chemistry question... Due to the Montreal Protocol (https://en.wikipedia.org/wiki/Montreal_Protocol) and subsequent phase-out schedule for all the “conventional” refrigerants, many/most of us in the HVAC service industry are consequently working with “interim” alternatives for...

Consider a sealed can of liquid refrigerant-134a in a room at 25 •C .Now if the lid is opened slowly and some refrigerant is allowed to escape, the pressure and temperature in the can start dropping rapidly.A thermometer inserted in the can will register -26°C when pressure drop to 1 atm. ,which...

Hey, I noticed that some manufacturers have provided data for pre-combined (2 or 3 modules) to achieve higher loads (limited to about 60 refrigeration tons).I was wondering if a designer could combine modules to achieve a greater even larger(different) loads or am i limited to the combinations...

http://www.pbs.org/wgbh/nova/physics/reaching-ultra-low-temperatures.html is this thing accurate? It uses methylene chloride as first refrigerant, then ethene, and then oxygen, and gets to liquefy air...down to 70kelvins after researching the very small info on the net about cascade...

Can we use same refrigerant for both air conditioner and refrigerator?

For the past year or so, I've been experimenting with Isobutane. I used to get it in relatively cheap canisters of r600a from amazon.com and AliExpress, and that worked fine. Now, however, AliExpress has NO purchase options for r600a, and amazon.com will not ship it to the US, even though they...

I am a little confused, because I know how refrigerators work with a refrigerant and a compressor and heat exchanges, and I am looking to build one myself, just wondering because I was looking for refrigerator compressors online to buy. Do they have an inlet for refrigerant or is the...

I'm a mechanical engineer and am learning about the different refrigerants used. 2 of them seem to be the most popular- R134a(C2H2F4) and R1234yf(C3H2F4). Why is it that R134a is rated at a Greenhouse effect(GWP) of 1430 where R1234yf is rated at a GWP of 4? Both refrigerants produce...

Homework Statement Does Coefficient of Performance for refrigeration cycle depend on refrigerant used? In reference to vapor-compression cycle Homework Equations COP = \frac{1}{\frac{T_{H}}{T_{L}}-1} The Attempt at a Solution I am split in my answer to this question. I...

Hi there, I am doing a project modelling and simulating a gas engine waste heat recovery system using an organic rankine cycle. As part of this project I would like to size the surface area of a heat exchanger (if only roughly). I have found the appropriate formula using Q = U.A.LMTD and...

I have a large volume of (free) natural gas sitting at 5,000 psi. I'd like to pass the gas through an orifice, give it room to expand on the backside, and use that to chill glycol. I would like to drop the output pressure to 100 psi in the process. I wish to use the chilled glycol to cool...

For doing modal analysis of suction and discharge side of an air-conditioning unit, is it needed to consider the inside refrigerant?

Can somebody give me a scenario when chilled beams would be the preferred method of conditioning and ventilation as opposed to the variable refrigerant flow systems? I have heard a lot about chilled beams, but I'm not sure they are ever going to really get popular in the US, because I don't...

Homework Statement 0.8kg of saturated liquid R-134a with an initial temperature of -5 °C is contained in a well-insulated, weighted piston-cylinder device. This device contains an electrical resistor to which 10 volts are applied causing a current of 2 amperes to flow through the resistor...

Hi guys, I'm stuck on some thermodynamic calculations and I would really appreciate some help! I'm trying to calculate the refrigerant temperature inside of an evaporator (two-phase lumped parameter model) based on the exit temperature of the evaporator and the pressure. I've understood that...

I believe that when refrigerant in an air-conditioner's evaporator boils into gas, the pressure on the refrigerant goes down tremendously. I believe that the drop in pressure on the refrigerant when it becomes a gas causes the temperature of the refrigerant to drop. I believe this because I...

I am going to be running some experiments with refrigerants. They will be at various temperatures and pressures. I will then be doing some modeling of certain phenomena. I would like to be able to quantify whether the ideal gas model is reasonable during certain stages of the experiment. My...

COP of a Refrigerant...Urgent Please Help! How do you find the COP ( Coefficient of Performance ) of a Refrigerant if you know the basic details of the refrigerant such as: Critical tempertaure Critical Pressure w Cp Also I am trying to calculate the VCC as well!? Any advice would be...

Howdy PFers! I hardly ever make it into this particular Forum, but I was wondering if any of you know of a refrigerant that evaporates at or around 50° F? Any assistance would be appreciated.

I am working on a project to design an organic Rankine cycle to convert low temperature thermal energy (waste heat or geothermal) into electrical energy. We are trying to select an expander to extract work from the pressure differential in the refrigerant. The refrigerant (ammonia or R134a)...