evaporating temperatures

[MrsFreeze]

Hello, I am trying to figure out how refrigerated display cabinets work and their specifcities according to the type of application.

In the course of my study, I need to identify the typical evaporating temperatures for various refrgieration equipment.

I was wondering of any of you had an idea of the figures for the evaporating temperatures in a
*1-door beverage cooler
*chest ice cream freezer
*cold vending machine

It would be of great help.

I also came up with figures for cooling capacities of the related compressors: do you agree with the following estimates?

For an evaporating temperature around -10°C
and a condensing temperature around 40 °C
*1-door beverage cooler ~0.4-0.6 kW
*chest ice cream freezer ~ ???
*cold vending machine ~ 0.5-0.8 kW

thanx in advance!

[Dave660]

depends what gas you runnuing on ?

[US Iceman]

Perhaps you can find the exact data you are looking for from the manufacturers themselves. Most of what you are looking for should be in their technical data for the cases.

Here are a couple of links to get you started.

http://www.hussmann.com/

http://www.tylerrefrigeration.com/

[Peter_1]

I was wondering of any of you had an idea of the figures for the evaporating temperatures in a
*1-door beverage cooler
*chest ice cream freezer
*cold vending machine

For an evaporating temperature around -10°C
and a condensing temperature around 40 °C
*1-door beverage cooler ~0.4-0.6 kW
*chest ice cream freezer ~ ???
*cold vending machine ~ 0.5-0.8 kW

Wow a US citizen using SI units

We can say that evaporating temperatures are gas independent.
You can take as a rule of thumb that the evaporating temperature in commercial refrigeration is 10 K to 15 K lower (smaller evaporators with higher DT) then the desired set temperature.

As US Iceman said for the power (don't confuse between absorbed and refrigeration power), better look in the catalogs of the manufacturers.

[Peter_1]

I was wondering of any of you had an idea of the figures for the evaporating temperatures in a
*1-door beverage cooler
*chest ice cream freezer
*cold vending machine

For an evaporating temperature around -10°C
and a condensing temperature around 40 °C
*1-door beverage cooler ~0.4-0.6 kW
*chest ice cream freezer ~ ???
*cold vending machine ~ 0.5-0.8 kW

Wow a US citizen using SI units

We can say that evaporating temperatures are gas independent.
You can take as a rule of thumb that the evaporating temperature in commercial refrigeration is 10 K to 15 K lower (smaller evaporators with higher DT) then the desired set temperature.

As US Iceman said for the power (don't confuse between absorbed and refrigeration power), better look in the catalogs of the manufacturers.

[MrsFreeze]

Thanks for your replies!!
It helped!

Dave> for appliances running on R134A

[Gary]

We can say that evaporating temperatures are gas independent.

Indeed. Similar systems have similar evaporating and condensing temperatures, regardless of the refrigerant used.

I used to tell people to black out the pressure scales on their guages with a magic marker and directly read the temperature scales for the refrigerant used, because the temperatures are what really matter.

I quit doing that because with all of the new refrigerants not having scales on the guages, they need P/T charts.

Still... it's about temperatures, not pressures.

[750 Valve]

Still... it's about temperatures, not pressures.

U betcha SST4ME

[Bones]

U betcha SST4ME

looks like you have a goof mouth full of that there mate

[mikefitz]

It's not polite to talk with your mouth full

[setrad7791]

1 Single door beverage evap temp -10
2 chest freezer -20/25
3 cold vending machine -5

[xpat-Aussie]

Evap temp should be around 10-15K below set point temp... so a single door beverage unit, would have a set point of around 5(c), therefore, the evap temp should be around -5 to -10(c).
Chest freezer set point would be around -18(c), giving us an evap temp of around -30(c) et cetera...
Some freezer applicaitons actually have a suction pressure that is a vacuum... someone already said, "forget about pressure"... best advice I've heard, and the same advice I gave to my apprentices for years!

So whether you're looking at the high or low side of the system, work in temperature. With so many refrigerant blends around these days, you'll be constantly converting pressure to temperature... but that's why we all have PT charts, they're essential!