That is the difference between a person reading a guideline and one review the guidelines.
The cources at Imperial College of Science and Technology and Medicine, in UK, provides lots of common sense values and rules of thumb.
I used to served in the Standards committees in Singapore, while I was there. I have compared many standard documents from different counties.
--------------------
The circulation pump is usually smaller. The one you have quated is large, 349 kW for 1000 L/s. Chiller pump can also be the compressor pump. They go in steps, because there is no such thing as a 20 to 300 hp variable speed pump. If there is, it will be inefficient.
In my last e-mail, I mentioned that the large chiller should be variable speed. Actually, in practice, they are moduler. A number of pumps brought into service as required. They can be as small as 10 hp. One of my installation uses 30 + 30 + 10 hp. compressors, pooled together to serve three AHU's on three floors. They can be used insteps of 10, 30, 40. 60, 70 hp.
-------------------------
The second question below is again common sense practice. One is a system and the other is zone, as I compare the numbers.
This is also the reason why the user here on VAV feeding 12°C air into a VAV damper get unusual results. A 53kw reheat heater in a zone? Something is wrong.
My design temperature for zone cooling air is 18°C with reheat, 24°C without reheat. You have 16/20 for secondary. It appears that primary is system and secondary is zone. 6/12°C is the temperature for a chiller or Dx coil lower limit.
80/50°C is the SHW and DHW tank setpoint. In the solar collector model, the tank is set to 80°C and trottled down to 65°C with the water main water mixer valve.
In UK, the steam radiator is actually hot water radiator at 50°C, which is warmer than the US system..
These terms have not much to do with EPlus capabilities. EPlus is universal, until you use some report for Comfort, etc. then the special values are incorporated. But you have a choice of not to use them or to use different schedules to fool the system.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: jeannieboef@xxxxxxxxx
Date: Tue, 25 Oct 2011 12:21:47 +0000
Subject: [EnergyPlus_Support] Re: How to model the primary/secondary pump system
__._,_.___
Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx
The primary EnergyPlus web site is found at:
http://www.energyplus.gov
The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/
Attachments are currently allowed but be mindful that not everyone has a high speed connection. Limit attachments to small files.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
![]()
__,_._,___
The cources at Imperial College of Science and Technology and Medicine, in UK, provides lots of common sense values and rules of thumb.
I used to served in the Standards committees in Singapore, while I was there. I have compared many standard documents from different counties.
--------------------
The circulation pump is usually smaller. The one you have quated is large, 349 kW for 1000 L/s. Chiller pump can also be the compressor pump. They go in steps, because there is no such thing as a 20 to 300 hp variable speed pump. If there is, it will be inefficient.
In my last e-mail, I mentioned that the large chiller should be variable speed. Actually, in practice, they are moduler. A number of pumps brought into service as required. They can be as small as 10 hp. One of my installation uses 30 + 30 + 10 hp. compressors, pooled together to serve three AHU's on three floors. They can be used insteps of 10, 30, 40. 60, 70 hp.
-------------------------
The second question below is again common sense practice. One is a system and the other is zone, as I compare the numbers.
This is also the reason why the user here on VAV feeding 12°C air into a VAV damper get unusual results. A 53kw reheat heater in a zone? Something is wrong.
My design temperature for zone cooling air is 18°C with reheat, 24°C without reheat. You have 16/20 for secondary. It appears that primary is system and secondary is zone. 6/12°C is the temperature for a chiller or Dx coil lower limit.
80/50°C is the SHW and DHW tank setpoint. In the solar collector model, the tank is set to 80°C and trottled down to 65°C with the water main water mixer valve.
In UK, the steam radiator is actually hot water radiator at 50°C, which is warmer than the US system..
These terms have not much to do with EPlus capabilities. EPlus is universal, until you use some report for Comfort, etc. then the special values are incorporated. But you have a choice of not to use them or to use different schedules to fool the system.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: jeannieboef@xxxxxxxxx
Date: Tue, 25 Oct 2011 12:21:47 +0000
Subject: [EnergyPlus_Support] Re: How to model the primary/secondary pump system
Hi Dr Li,
Good to see you here. Your interpretation is very good for someone without the document. I've just read this section in the users manual for the 90.1 code. It's about reflecting the chilled water pumps pumping power.
As I understand it, one must have two pumps for systems larger than 300 tons. One runs constant (primary) and the other variable (secondary).
Nominal Pump Power is 349 kW per 1000L/s. The variable pumps ride the pump curve.
The number of chillers one is asked to use is given in another table and depends on cooling capacity in tons. Sometimes they must be sized equally, other times not.
.........................................
Still I would love to know how to do a primary secondary system for cooling (6/12°C primary, 16/20 secondary) and heating (80/50°C primary, 28/24 secondary), where primary water goes to AHU coils and secondary water goes to radiant systems.
So far I've been using different plants for these systems, but I'm sure e+ can do better than that.
Good to see you here. Your interpretation is very good for someone without the document. I've just read this section in the users manual for the 90.1 code. It's about reflecting the chilled water pumps pumping power.
As I understand it, one must have two pumps for systems larger than 300 tons. One runs constant (primary) and the other variable (secondary).
Nominal Pump Power is 349 kW per 1000L/s. The variable pumps ride the pump curve.
The number of chillers one is asked to use is given in another table and depends on cooling capacity in tons. Sometimes they must be sized equally, other times not.
.........................................
Still I would love to know how to do a primary secondary system for cooling (6/12°C primary, 16/20 secondary) and heating (80/50°C primary, 28/24 secondary), where primary water goes to AHU coils and secondary water goes to radiant systems.
So far I've been using different plants for these systems, but I'm sure e+ can do better than that.
__._,_.___
Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx
The primary EnergyPlus web site is found at:
http://www.energyplus.gov
The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/
Attachments are currently allowed but be mindful that not everyone has a high speed connection. Limit attachments to small files.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Your email settings: Individual Email|Traditional
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe
__,_._,___