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pablok
02-26-2016, 01:02 PM
I'm working with a client (a fast food chain) on a refrigeration replacement project. The installer/HVAC/R contractor said they don't recommend using systems with hot gas defrost because not all refrigeration service techs know how to service hot gas defrost units, and because they are most expensive. I'm a proponent because they are more efficient. (I do energy work/not a tech).

Do you all agree that a lot of techs don't know how to service these type of systems? I'm guessing a lot of guys that spend time on here would, but what about average Joe tech taking a call from a fast food restaurant?

reprmnmt
02-26-2016, 01:13 PM
I don't know about the cost of the equipment but hot gas defrost is easier than an electric defrost circuit to work on. They certainly use less energy than a defrost circuit.

The_Sale
02-26-2016, 01:44 PM
Hot gas defrost is so nice. I have a store that I haven't had to manually deice a single case in in the 7 years I've been servicing them.

VTP99
02-26-2016, 01:55 PM
Yeah, look at every ice machine except maybe Mani Cool Gas.
Get in / Get out is BEST !

pecmsg
02-26-2016, 02:15 PM
Do you all agree that a lot of techs don't know how to service these type of systems? t?

A lot of "TECHS" cant service anything, they just change parts and hope to get lucky!

Go with hot gas!

CFESAmasterEGSR
02-26-2016, 02:18 PM
I do fast food refrigeration.

My personal favorite is the master built reverse cycle defrost.

But as far as energy savings, the KE2 Evaporator Efficiency System on standard electric defrost is a very efficient system. Or it can do hot gas if you want to do that.

For energy efficiency I would look into the KE2 Therm Solutions offerings.


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icemeister
02-26-2016, 03:07 PM
How many systems are there in a fast food restaurant that could use hot gas defrost? One or maybe two walk-ins perhaps? The kitchen would have small freezers on the line but it's unlikely you'll find any of those available with HG defrost.

What is the projected energy savings for HG vs electric defrost for the freezers in your project. How long is the payback on the added initial cost for HG vs electric?

If you have systems which are proprietary in nature, the service replacement parts are unlikely to be readily available locally. That often means the lack a simple temperature replacement may take 2 days or more to complete due to the lack of parts.

Personally I prefer the operation of HG over electric defrost, but I only recommend it where it is would be the best choice overall. I just don't see how the benefits would outweigh the costs here.

lytning
02-26-2016, 05:55 PM
X2, they just change parts and hope to get lucky!

Go with hot gas![/QUOTE]

Mike19
02-26-2016, 05:57 PM
I've heard the reason that Walmarts are all electric defrost is because they're afraid not all technicians would know how to work on hot gas defrost.

Not sure if its true or not.

pablok
02-26-2016, 08:41 PM
I do fast food refrigeration.

My personal favorite is the master built reverse cycle defrost.

But as far as energy savings, the KE2 Evaporator Efficiency System on standard electric defrost is a very efficient system. Or it can do hot gas if you want to do that.

For energy efficiency I would look into the KE2 Therm Solutions offerings.


Sent from my iPhone using Tapatalk


We piloted the KE2 Therm at the same QSR last year with limited success (still working on the savings figures). I think the big issues we ran into were poor or incorrect installs and programming. (from the same contractor that says not to use hot gas...hmmm). Installations on old, broken down systems that probably shouldn't have received them, and in a couple cases the local techs removed them.

With the installs problems, there were sites that were defrosting 12 times a day after the KE2 installs. My take away from using them was that they are a good solution if you have an engaged local tech and can go back to make tweaks to the settings or sensors.

We're still thinking about using them factory installed for new systems, but I still have to be convinced.

pablok
02-26-2016, 09:02 PM
These are for the WIC and WIF. One each, small boxes 12x15 probably.

I haven't figured out the energy savings for HG yet. I don't really even have a starting point for that as there isn't a lot of calculators or data out there other than a pretty universal acceptance that HG uses less energy. It makes sense since the it's using the heat that was already created.

All of them are standard packaged systems. No custom build refrigeration systems. HG equipment is supposedly 30-35% more expensive, but I'm still waiting on that pricing.

Mike19
02-26-2016, 09:45 PM
I'm working with a client (a fast food chain) on a refrigeration replacement project. The installer/HVAC/R contractor said they don't recommend using systems with hot gas defrost because not all refrigeration service techs know how to service hot gas defrost units, and because they are most expensive. I'm a proponent because they are more efficient. (I do energy work/not a tech).

Do you all agree that a lot of techs don't know how to service these type of systems? I'm guessing a lot of guys that spend time on here would, but what about average Joe tech taking a call from a fast food restaurant?

Half the "refrigeration techs" out there could work on it without issue, but the other half of them would get very confused if the system they have to work on is too complicated.

Whenever something breaks they will change a lot of parts that aren't bad, and the system will be down for a while as they fumbles their way through it.

Its sad, but its the world we live in.

icemeister
02-26-2016, 11:24 PM
These are for the WIC and WIF. One each, small boxes 12x15 probably.

I haven't figured out the energy savings for HG yet. I don't really even have a starting point for that as there isn't a lot of calculators or data out there other than a pretty universal acceptance that HG uses less energy. It makes sense since the it's using the heat that was already created.

All of them are standard packaged systems. No custom build refrigeration systems. HG equipment is supposedly 30-35% more expensive, but I'm still waiting on that pricing.

Unless the walk-in cooler is running below 35 Deg F it wouldn't require either hot gas or electric defrost.

As for HG being more efficient and universal acceptance of that belief, it all depends on who you talk to, how you analyze the numbers and what type of system you have. In the supermarket business for more than fifty years this has been an ongoing debate and it's not resolved yet. I was involved in supermarket engineering decisions some 30 years ago and if you include first costs for equipment, installation material and labor, power system requirements, etc and then maintenance cost of one vs the other I say it really come down to preference because the long term dollars are a wash.

For small single installations I think the sales record of light commercial electric defrost vs HG systems over the same time period will show that there's not a huge incentive out there to use HG defrost for such applications.

When you say that HG uses energy that's already created, that is true for parallel compressor systems like in a supermarket where there is a constant supply of "free" hot gas for defrosting. This isn't true for single compressor systems. For HG defrost the compressor must continue to run to develop the energy for defrosting while the compressor shuts off for electric defrost. Surely the energy used for an defrost cycle may be more that what would be needed for a HG cycle, but it's not as much as you have been led to believe.

BALloyd
02-26-2016, 11:31 PM
If you go electric defrost and they do not all ready have it, it will likely need more wire pulled and/or an electrical upgrade. Just something to consider.

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Red Man
02-27-2016, 12:27 AM
Last year the company I work for put in a walk in freezer with reverse cycle defrost. It's a heatcraft unit that has a reversing valve like you'd see in a heat pump. No problems yet, seems like a pretty cool idea. There's really nothing complicated about it and I don't think it was very much more money.

VTP99
02-27-2016, 09:15 AM
I agree with Red Man. IMO reverse hot gas is the best hot gas method.

lytning
02-27-2016, 01:10 PM
Any one ever replaced electric to hot gas because the electric failed.
I agree with Red Man. IMO reverse hot gas is the best hot gas method.

icemeister
02-27-2016, 02:45 PM
The only true reverse cycle defrost system is Russell's High Sierra:

http://russell.htpgusa.com/images/documentation/products/high_sierra/ru-dhd-0712a.pdf

Their energy savings claims come primarily from their floating head pressure. They don't seem to break out any savings attributable to the hot gas defrost.

Heatcraft, as far as I have found, only makes two pipe hot gas defrost systems from 6 HP and up.

Mike19
02-27-2016, 02:55 PM
The only true reverse cycle defrost system is Russell's High Sierra:

http://russell.htpgusa.com/images/documentation/products/high_sierra/ru-dhd-0712a.pdf

Their energy savings claims come primarily from their floating head pressure. They don't seem to break out any savings attributable to the hot gas defrost.

Heatcraft, as far as I have found, only makes two pipe hot gas defrost systems from 6 HP and up.

Master-Bilt has a similar setup, except it uses one eev at the evaporator, to act as a metering device both ways.

UmmScott
02-27-2016, 03:02 PM
Master-Bilt has a similar setup, except it uses one eev at the evaporator, to act as a metering device both ways.
We service a few of those systems here in omaha.
Pretty slick...when they work right lol

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Red Man
02-27-2016, 04:27 PM
The only true reverse cycle defrost system is Russell's High Sierra:

http://russell.htpgusa.com/images/documentation/products/high_sierra/ru-dhd-0712a.pdf

Their energy savings claims come primarily from their floating head pressure. They don't seem to break out any savings attributable to the hot gas defrost.

Heatcraft, as far as I have found, only makes two pipe hot gas defrost systems from 6 HP and up.

I was wrong, its not heatcraft. It is the Russell high sierra.

icemeister
02-27-2016, 06:27 PM
Master-Bilt has a similar setup, except it uses one eev at the evaporator, to act as a metering device both ways.

Duh....I forgot you had mentioned the Master-Bilt system the other day. Sorry.

There are two signs of old age. One is loss of memory. I don't recall what the other one is. ;)

icemeister
02-27-2016, 07:13 PM
If you look at the MasterBilt system with the heat-pump-like hot gas defrost it's a lot like the Russell system. They both claim huge energy savings...depending on where you are.

That just says the savings is all about their floating head pressure, not the HG defrost.

Again I will say that these system may be "cool" and "really, like fast". Ya I know all that too. The reality is while I prefer HG defrost as a tech, I can't recommend one of these for a customer if I can't service it quickly.

I said the same thing about the Heatcraft Beacon systems which have been around a lot longer. Back when I was actually interested I went to my local Heatcraft distributor and asked a few pertinent, yet pointed questions regarding availability of service parts for the Beacon.

First I asked if I had just installed one and needed a replacement sensor would you have one on the shelf...or better yet...do you have one on the shelf right now? "Well no, we don't have one now, although we have had them but they keep getting kicked off the shelf stock list, but I can always get one from the region warehouse next day UPS...if they have one...otherwise it's another day or so,,,and if we have to pull from the factory...there's a minimum order...YADA,YADA,YADA."

That was all over a sensor. The one part on that system with the highest known failure rate known to man and they couldn't guarantee to have one on hand.

I had the same sad story when I got all excited about the Copeland XJAL outdoor condensing units for low temp with vapor-injected R404A scrolls. They would save so much money you could pay for your kids college education without breaking a sweat. I had the pricing and a customer anxious to buy, but I had to tell him no.

If you're willing to gamble with your customer's money and trust, please go right ahead. I wouldn't and I didn't.

Mike19
02-27-2016, 07:32 PM
Another thing about the systems with electric expansion valves and sensors, like the master-bilt, Russell, and beacon systems too.

I've encountered it so many times where another tech will condemn the eev, or condemn the board, and I will go there to find the system is just low on refrigerant or has a weak compressor or a dirty condenser or a plugged drier, or something like that.

I think of all the times someone has condemned an eev, maybe like one in ten times or so it was actually the eev.

Mike19
02-27-2016, 07:35 PM
If you look at the MasterBilt system with the heat-pump-like hot gas defrost it's a lot like the Russell system. They both claim huge energy savings...depending on where you are.

That just says the savings is all about their floating head pressure, not the HG defrost.

Again I will say that these system may be "cool" and "really, like fast". Ya I know all that too. The reality is while I prefer HG defrost as a tech, I can't recommend one of these for a customer if I can't service it quickly.

I said the same thing about the Heatcraft Beacon systems which have been around a lot longer. Back when I was actually interested I went to my local Heatcraft distributor and asked a few pertinent, yet pointed questions regarding availability of service parts for the Beacon.

First I asked if I had just installed one and needed a replacement sensor would you have one on the shelf...or better yet...do you have one on the shelf right now? "Well no, we don't have one now, although we have had them but they keep getting kicked off the shelf stock list, but I can always get one from the region warehouse next day UPS...if they have one...otherwise it's another day or so,,,and if we have to pull from the factory...there's a minimum order...YADA,YADA,YADA."

That was all over a sensor. The one part on that system with the highest known failure rate known to man and they couldn't guarantee to have one on hand.

I had the same sad story when I got all excited about the Copeland XJAL outdoor condensing units for low temp with vapor-injected R404A scrolls. They would save so much money you could pay for your kids college education without breaking a sweat. I had the pricing and a customer anxious to buy, but I had to tell him no.

If you're willing to gamble with your customer's money and trust, please go right ahead. I wouldn't and I didn't.

I agree.

I had a Beacon board fail, and the customer ended up emptying out the walk in freezer because the board had to get next-day aired from a warehouse in Kentucky, lol

There has been a few times we've had a board or eev fail, and we ended up just ripping the beacon stuff out and putting in a txv, thermostat, solenoid, and time clock.

The reliability and parts availability is a big factor. We have a supermarket that runs eev's in the cases. The sensors, transducers, boards, and valves go bad all the time. The failure rate of the electronic junk is astronomically higher than the failure rate of a regular txv.

joejax
03-02-2016, 08:52 PM
Hot gas=more problems. Especially if you have an EEV. The BasterdBilt systems are way over engineered. K.I.S.S. We run -40 units with 1 electric defrost per 24 hours with no problem. The hot gas units are fouled up beyond belief and they are dialed in to run -43 F with a factory 4 per 24 defrost.

joejax
03-02-2016, 09:47 PM
And God help you if you get a leak on the low side and get moisture in the system. EEV, reversing valve and possibly, the compressor, all ruined. Spend the next week trying to get the water out.

I just went through all of this recently. Although, my application may differ, my disgust does not. After a week of vac and purge, hold at 400 microns, the EEV was stuck open on start up.

In a mad rage and at a box temp of -34F, I blasted the valve with a propane torch to get it going again. Unbelievably it worked.

With the big wigs biting at my neck, I had to fire up the other unit on this box which has the 2, 12 hp units, to get the box temp pulling down......before I could start the other.