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rickmor
14-05-2005, 10:01 AM
I am thinking of purchasing a walk-in chiller/freezer for a very cheap price. This is unit is unused and was meant for a busted project. The size of the unit is 5.45m x 7m x 2.4m, divided almost equally between the chiller and freezer. The freezer's compressor is a Copeland Discus 2DL3-040E-TFC-200, while the chiller has a Copeland semi-hermetic NRM1-0500-TFC-200. My problem is that I don't have the need or the space for such a large walk-in. I was thinking of just installing half of the walk-in, such that the new dimensions would be 2.8 x 7 x 2.4, keeping the remaining panels for some future expansion. I will end up with an oversized refrigeration system for my walk-in.

Will my energy consumption be proportionate to the new size of the walk-in? Will halving the size also approximately halve my energy consupmtion? Secondly, can my freezer approximate the performance of a blast freezer, considering that the refrigeration unit is so large?

chemi-cool
14-05-2005, 11:41 AM
Hi Rickmor,

You ask many questions,
i will try to put it in order,

By reducing the size of the chiller room, the refrigeration unit will work like on short cycle, its best to change it to an adequate size unit, and cut the running costs .


You can not use the freezer unit as a blast freezer,

You will need diferent evaporator and fans.
Since the unit is designed for a freezer, it can not work in high evaporating temp, you will also need to install evaporation pressure controll and suction pressure controll.

Or in other words, you will need to redesign and build it.

Chemi :)

rickmor
14-05-2005, 12:59 PM
Thanks for the info. I am getting the walk-in as a package, and therefore will have to use the included refrigeration system. Will my power consumption be much higher running on short cycles as opposed to using a smaller system?

chemi-cool
14-05-2005, 01:03 PM
Not if you add a timer to set off time for at least 20 minuets.

Set the temp for 2c lower then what you want as the unit will cool the air in the room quicker but for the products it will take the same time too cool,

Set the differential (hysteresis) for 2c more then it was.




Chemi :)

rickmor
14-05-2005, 02:21 PM
I probably won't be using the chiller for now, since we don't really have that much to chill. We do freeze quite a bit, and although in know that I need a blast freezer to produce a better product, I don't have the budget for it right now. Our main product that we freeze is a mango torte, which goes into to the freezer at room temperature. It's a relatively thin product, similar in dimension and weight to a pizza so it freezes quite rapidly.

Although I know the set-up is not ideal, the price is just too tempting to pass up. It will cost around US$5000 for the specifications I listed above. All panels are made with 100mm polyurethane insulation and includes condensers and evaporators, all of which are brand new (2001).

Peter_1
14-05-2005, 03:36 PM
What kind of evaporators are connected to the compressors?

..freezer's compressor is a Copeland Discus 2DL3-040E-TFC-200, chiller ..Copeland semi-hermetic NRM1-0500-TFC-200.
You can change the sort of gas to limit temporarily compressor capacity (from R404a to R134a) Compressors are quality machines.

Will my energy consumption be proportionate to the new size of the walk-in?
Energy consumption for an empty room is determined by the wall losses (very Little in your case because you're using PU panels of 10 cm), in the order of some 100 Watts.

Will halving the size also approximately halve my energy consumption?
For the chiller, energy consumption is determined by the goods you bring in the room: temperature, weight of the goods, and kind of goods (vegetables or meat) If it's only half the size, you then only have half the space available to store the goods, so consumption will be half.
Remember that the RH of the room will be very high because unit will perhaps run not long enough to remove the moisture.

Secondly, can my freezer approximate the performance of a blast freezer, considering that the refrigeration unit is so large?
Depends on what you wants to freeze, how much, how fast, how the goods are stored in the freezer (very important), ... but I should say for the size of your room...yes.
Capacity in a blast freezer is mainly determined by the weight and the freezing time. The rest can be minimized.

Try to find the type of the freezer evaporator, fin spacing and number of resistances.
You will perhaps need additionally some fans to improve wind velocity, a false ceiling and an airturn.
Give me an idea how many of these mango tortes you want to freeze in a day and what the weight is of one torte. It will definitely improve the quality of your product if you can blast freeze it.

You can send the Mango tortes now to my address, 10 is enough to start with :p

rickmor
16-05-2005, 03:52 PM
Peter,

Thanks for the advice. I don't have the specs for the evaporator or the condenser yet, but I'll get it soon. You're too far for a freebie, but if you find your way in our neighborhood, I'll be sure to give you some. :D