Digital scroll

[Camalla]

Hi,
I'm new in this forum and in this field/market

has anyone heard about Copeland digital scroll and its performance in hydronic systems (chillers / heat pumps)?

any idea on how to control it? how would you drive the EXV given the pulsating nature of the compressor?

thanks fo your help

[nike123]

Try to find something from this manual:
http://tinyurl.com/65v5xh

[Camalla]

Thanks a lot nike123

this is a manual for a VRF system, multievaporators, very interesting

any idea if there is something available also for hydronic, single evaporator systems?

[Camalla]

Thanks a lot nike123

this is a manual for a VRF system, multievaporators, very interesting

any idea if there is something available also for hydronic, single evaporator systems?

[Sridhar1312]

Is it possible to control temperarure and Relative Humidity with only Electronic Expansion Valve.If it is possible, kindly explain how it is achieved.

[CHilly1]

TO Control RH you lower the capacity to increase run time while keeping the evap under dew point. To Raise RH (provided you have enough moisture input to begin with an empty cooler with no aspirating media would not work or you add humidifier) You Raise Capacity over that neassassary to cool the space to shorten the run time thereby cooling in the shortest possiable time removing as little as possiable moisture.
IN Meat curing roms we use Freezer coils Wide range TXV's and small misters. the Misters are set at the min Humidity nessassary the heaters are set at the maximum Humdity, and system capacity is designed by load calcs plus 10%, this system is very energy unconscious but it is simple. The electronic TXV would be the best but still would need some form of humidification occationally.

[GXMPLX]

Is it possible to control temperarure and Relative Humidity with only Electronic Expansion Valve.If it is possible, kindly explain how it is achieved.

No, you can not. As Chilly1 says, the only possibility is to lower it until you reach a point above the coils dew point at the set temperature. But the final air water content will depend on other conditions (moisture given off by the product, infiltration conditions, etc)! Only if you have no added moisture you could know final relative humidity. With normal TXVs you cannot do even this but you are not controlling it in the way I understand "controll".

[Peter_1]

Hi,
I'm new in this forum and in this field/market

has anyone heard about Copeland digital scroll and its performance in hydronic systems (chillers / heat pumps)?

any idea on how to control it? how would you drive the EXV given the pulsating nature of the compressor?

thanks fo your help

Together with the compressor, they deliver also the proper controller for the valve.
You don't have pulsations with a scroll and you even don't see pulsations with the digital scroll while throttled. The pulsations are flattened out in the evaporator and condenser.
If you should see pulsations, the you should see those also with the EEV's from Danfoss (AKV's puls/pause principle)

[star882]

Is it possible to control temperarure and Relative Humidity with only Electronic Expansion Valve.If it is possible, kindly explain how it is achieved.

With just an electronic expansion valve, no. But it is part of a system that allows precise temperature and humidity control.
Basic idea is to modulate system capacity (compressor speed and expansion valve restriction) to regulate amount of cooling and air handler fan speed to optimize the system for dehumidification or cooling. Since A/C systems are more efficient at part load, a smart controller can try to run the compressor at low speeds when possible. The air handler fan runs at lower speeds in relation to compressor capacity for more effective dehumidification.

[urajat]

I know one manufacturer blue star they manufacture VRF system with digital scroll. Humidity is controlled by controlling dt of evaporater and heaters. for humidification humidifier is used.

[thmech]

I heard that, in VRF system, digital scroll is better than inverter in term of dehumidification because of....(I am not quite clear)... Can someone explain in details why?

[abbasi]

We have installed many digital scroll systems and yes it is way better than inverter system in all respects.
Digital scroll capacity modulation is from 10% to 100% with respective power consumption of 10%-100% also it has very less rather none electronic components compared to inverter system. Inverter cannot run below 40% compared to 10% of digital compressor system. EER of digital scroll is way higher than best japanese inverter in market.
I have whole presentation in this regard. I can email you if you want. Also click link below
http://www.digitalscroll.com

[abbasi]

I heard that, in VRF system, digital scroll is better than inverter in term of dehumidification because of....(I am not quite clear)... Can someone explain in details why?

It has low sensible heat ratio (LSHR)that is sole reason of better dehumidification +-2%

[thmech]

[/quote]

It has low sensible heat ratio (LSHR)that is sole reason of better dehumidification +-2%

I am so busy for while, by the way thank you.


[quote=abbasi;126939]We have installed many digital scroll systems and yes it is way better than inverter system in all respects.
Digital scroll capacity modulation is from 10% to 100% with respective power consumption of 10%-100% also it has very less rather none electronic components compared to inverter system. Inverter cannot run below 40% compared to 10% of digital compressor system. EER of digital scroll is way higher than best japanese inverter in market.
I have whole presentation in this regard. I can email you if you want. Also click link below


Yes, I am interesting in that presentation so can you mail it to me at kobj03 yahoo mail.

[mekaniko5]

We have installed many digital scroll systems and yes it is way better than inverter system in all respects.
Digital scroll capacity modulation is from 10% to 100% with respective power consumption of 10%-100% also it has very less rather none electronic components compared to inverter system. Inverter cannot run below 40% compared to 10% of digital compressor system. EER of digital scroll is way higher than best japanese inverter in market.
I have whole presentation in this regard. I can email you if you want. Also click link below

Sound good. What application have you used the Digital Scroll system with? What OEMs did you use?

[Thermatech]

You need to check out the facts yourself.

From personal experiance & technical manuals to hand i find that the information in the Emerson presentation to be highly misleading. Ofcourse any manufacturer will try to spin information to make there product look like the best product available.

But the claims about poor performance of VRF systems are completely overstated & mileading when checked against technical data for leading VRF manufacturers.

If any critical investigation of all digital scroll manufacturers was undertaken & one negative point taken from each & then the accumulation of all those negative points compared to the best VRF system, then the presentation would clearly show that VRF is much better than DS.

When viewing any manufacturers presentation about the features & advantages of that product you do need to be able to see past the smoke screen & spin & mis information.

You very often will find the advantages of the product overstated & the disadvantages of the competition overstated & the benifits of the competion not mentioned at all.

[mekaniko5]

It is interesting to find VRF systems being applied where traditional A/C systems have been commonly used in the past. High rise buildings, commercial complex with huge spaces now use VRF systems specially in Asia.

[nike123]

It is interesting to find VRF systems being applied where traditional A/C systems have been commonly used in the past. High rise buildings, commercial complex with huge spaces now use VRF systems specially in Asia.

That doesn't mean that VRF is technically better solution than Digital Scroll or water chiller systems.
Compare that with VHS and BETA video system.
Beta is much more advanced but VHS is commercially cheaper and simpler to produce. Availability wins over technical excellence when customers are wiling to tolerate that.

[mekaniko5]

That doesn't mean that VRF is technically better solution than Digital Scroll or water chiller systems

Digital Scroll Compressors are actually being used for VRF System.

The main difference from other modulated capacity system more commonly named as VRVs is that the motor runs at a fixed speed rather that variable speeds.