New TFC regulator

[Carlo Hansen]

Hi Guys

I has been working with milk cooling tanks for many years at RO-KA Industries.it is mostly customer designed milk cooling tanks and we had problems with ice building on the evaporator by using robotic milking plants since the only deliver max 75 Ltr/h. to the tank.About 4 years ago there came a guy and he presented a new patented TFC regulator to us.This regulator could replace the termal expansion valve and lower the power consumption with up to 20% and also run the evaporator, without ice building by a very small amount in the tank.This was really interesting so we decided to try it.The results we achived was really good,the evaporator runs now as a full flooded evaporator, there is no ice building at all by a amount of 2-3% of the rated tank volume and the power consumption is lowered with up to 15%. In this moment there is running about 50 milk cooling tanks with this system and they runs really good.
This TFC regulator has shown very good results also for cold or freezing stores. If anyone would like more information about this TFC then see the link below and feel fre to mail me.

http://www.wulffdata.dk/English/index.htm

Best regards
Carlo

[chemi-cool]

Thanks for the information Carlo.

It sounds good but there is not much on their website.

Can you also post some pictures?

Chemi

[Carlo Hansen]

Hi Chemi

I think i a can send you some photos of the first milk cooling tanks and some test i has made, just give me 2-3 days.

Best regards
Carlo

[Carlo Hansen]

Hi Marc

I think the LPR system is nearly the same as the HPF system
( HiPerForm ) I also think ther was an notice witch
said there was 2,5 % engergi sawing with the LPR system.
And yes, if there is not taken special precations to secure
the oil returning, there could be problems with this systems.
We do not have any problems by returnig the oil to the compressor, we has just taken normal precations to the
evaporator,pipping etc.

Best regards
Carlo

[Carlo Hansen]

Hi again

Here is a couple of photos of the TFC regulator, and test result for a 2500 litres tank designed for robotic milking plant.
I think the test result and the cooling diagram tells a lot more
about the system.

Best regards
Carlo

[RogGoetsch]

In essence, is there an advantage to this system compared to employing a suction-to-liquid heat exchanger of the same capacity?

Another way of asking: is there an advantage to supplying lower-pressure liquid to the final expansion device, if the liquid temperature is the same?

If the final expansion device can operate effectively at a lower pressure drop, why not use this advantage to lower condensing pressure, when ambients permit, instead of intermediate pressure? Wouldn't that provide a far better C.O.P.?

Rog

[Carlo Hansen]

Hi Rog

You will have to look at the hole system, and this system has the benefits to run the evaporator as a overflodded system,if
you are employing a heatexchanger to a normal system with TEV, you will not have a overflodded evaporator, but the COP will increases with 11 % with the refrigerant R404A and make a loos at -1 % with the refrigerant R22.
The fact is this, with the TFC the COP will increase with up to
18 % with R404A, and 7 % with R22.

You also ask if there is any advantage to supply the cold nozle with lower pressured liquid, the intermediate pressure in the the heatexchanger controls the TFC system and has no thermo-dynamical influence.

Concerning the condensing temperature you has right into a point, because it will be nessesary to obtain a pressure difference between the evaporator and condenser to keep the right refrigerant flow in the system.
The condensing temperature follow the ambient up and down to the min. settings we have calculated for the system, and this is done to secure the compressor by very low ambient temperatures.

Best regards
Carlo

[RogGoetsch]

Hadn't seen the system schematic diagram earlier (Dok5.doc), just figuring from the pressure-enthalpy diagram from the first posting, I wasn't seeing the difference between this and a system similar to what Marc mentioned. (Why between the hx's and not after, Marc?)

Very nice system, Carlo. Beautiful way to get the most out of your evap and make sure you don't freeze the milk.

I see now that the purpose of the hot nozzle is to maintain condensing pressure during low load so that the capacity control can function as needed, keeping suction pressure above freezing. (I think the sensing line from the capacity control head is intended to run to the downstream side instead of as shown?)

I still miss the good old ammonia days when we designed winery systems with 3:1 pumped liquid overfeed and let the condensing pressure drop as low as it could. Now THAT's a flooded evap and great C.O.P.! (Not that those systems aren't still going in, it's just that I'm not doing it.)

We just need a safe refrigerant lighter than oil and we can get there again even for small applications. Anyone working on that?

Rog

[Dave Goodings]

Hello Guys
This seems a good system but I seem to be missing the point in using this in Bulk milk tanks as there is no ice on the evaporator with this system, I thought the point of milk tanks was that you build a ice bank for thermal storage thus using a smaller condensing unit to cope with high initial cool down loads my apologies if I have misread this thread
Regards
Dave G

[chemi-cool]

Hi Dave.
Yes, you missed the point.
Carlo's system is a DX system.

In the USA and now also in Israel where the dairies have more then 500 milking cows, the bulk milk tanks are using what we call Pre-cooling system that works on ice water from an Ice bank or ice water chiller that cools the warm milk via plate heat exchanger.

In Europe, most of the dairies are small, up to a 150 milking cows.
This is a good market for Carlo's units.

Chemi

[Carlo Hansen]

Hi Rog

Thanks Rog, You are right cocerning the drawing of the capacity regulator.We always mount a capacity regulator
on units with TFC for Milk Cooling, and this is normally only in function by 2-5 % of milk amount in the tank.
You mention small units, we has made a lot of test with household freezers (not the kind You are looking for, I Think) We has made test with the Mini-TFC in freezers to achieve the A++ certification.These test was with the refrigerant R134A and R600A, And they all show the same good performance. the Mini-TFC replaces the capillary tube and allow +/- 10 % of refrigerant filling in the freezer.This is interesting, specially for R600A, because the refrigerant filling in a system with capillary tube and R600A most be exstremely precise acording to the ambient temperature.
I attach test data from a freezer test.
For now there is 2 companies witch use the TFC. See the link below. RO-KA make TFC units from MTZ 22 to MTZ 160

Best regards
Carlo

http://www.lillnord.dk/eng-sider/news.html

http://www.ro-ka.com/SEEEMS/66.asp

[Carlo Hansen]

Hello again

There is now a program to simulate the diff. of TFC and capilary
tube in freezers, this is a beta version. I think you can use this
this to compare the TFC system against typical cooling systems.

Download the ( simuleringsprogram ) from this link.

http://www.wulffdata.dk/Dansk/Mini-TFC%20oversigt.htm

Best regards
Carlo Hansen

[chemi-cool]

Hi Carlo,


מדוע הלינק בדנית

Or in English, why is the link in Danish?

Can you direct me to the right place?

Chemi

[Carlo Hansen]

Hi Chemi

You are right the link is on danish, but the TFC simulator
is in english, and the name is simuleringsprogram

Best regards

Carlo

[chemi-cool]

Hi Carlo,

From some reason, it doesn't open.

Can you check it again?

Chemi

[Carlo Hansen]

Hi Chemi

You will have to download the program and find it on your PC
and then you will have to unzip the program.
It seems to be a problem to open the file direct from the link.

Best regards
Carlo Hansen