T.T
See my reply below'
Mark all the names used in the IDF on your schemetic. Every item you need are there. One part that is not shown in your schematic diagram is the coil in the DHW tank. There are others. Doing this exercise will help you to understand the process and design.
Do not worry of the the names, heater, boiler, water tank, intermediate tank, heating tank. They may be called differently in different part of your diagram.
The boiler is a furnace with a fire. The gas fire boiler object is in the hotwater plant loop.
If the furnace has a water jacket, that is part of the HW tank.. The temperature of this is monitored with a thermostat and controls the gas fire.
The HW boiler plant loop is a closed water loop. This loop feeds all the radiators and the coil in the DHW tank. This is shown correctly in
your simulation. The reason why you do not see the result is simply you did not ask them to be displayed in timestep interval and the schedule values may be wrong. Do not add any more setpoint manager,etc, because you are not in the position to use them yet. EMS parts are not in your real system.
I suggest that you should identify all the names in the IDF and mark them on your schedule. Then find all the values for each representative time step at a certain ODT. (Night, morning, noon, afternoon, etc.) If you cannot find the name or values, ask again using one IDF only.
The DHW tanks has a float valve, as you turn the tap, the hot water is used, and the tank is filled from the water main at a low temperature. You never mentioned this, and I assume that you do not know how this is done. You never mention where the DHW tank is. I assume that it is at the roof top. All
these details, you must find them and add them to your schematics.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: t.t111ir@xxxxxxxxx
Date: Fri, 17 Feb 2012 18:47:34 +0000
Subject: Re: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
Dear Dr.Li
i read this :
A hot water heater is the storage tank of water that is responsible for the supply of hot water to the many fixtures in the house, such as showers and sinks. I know that, that is why I always refer it as the DHW tank. You do not realize the difference because you did not show the HW heating coil in the tank.
It does NOT supply heat for the home itself. There are two basic types of water heaters, one that runs on gas or some other fuel and one that runs on electric. The electric heater is probably in the DHW tank and is called the auxiliary heater in the EPlus simulation. This is not in the IDF yet. When the boiler is turned off in Summer, the DHW can be supplied using this electric heater. The rating is usually about 3Kw for a 10 gallon tank. The electric heater has its own thermostat, and will turn on and off at a lower water temperature. This may be the 65°C you were talking about.
A boiler on the other hand IS responsible for the heating of a home itself. Water or steam in a boiler reach much higher temperatures than the water in a hot water tank and therefore its used for heating and not drinking water or potable water. Portable water is never supplied from the DHW open tank.
In a steam system for heating, pipes run throughout the house from the boiler carrying steam that eventually gives off its heat at the many radiators. In a hydronic system for heat, smaller pipes carry hot water to various baseboards around the house that release the heat using circulator pumps to push the water through and back to the boiler. Are you talking your real system or another system? If the thermostat is set at 80°C it is not a steam, although they are referred to as "steam" radiators so that people would not place their hand on it. This why EPlus has a separate low temperature hydronic radiant model.
the building that i modeled : the boiler has thermometer and the heater that includ portable water doesn have thermometr it is heat exchanger that has two coil one for hot water from boiler and another for shower ,sink,... Thermometer is not thermostat.
could you please help me
thanks
I do not need to read more from Wiki. Read the EPlus manuals.
You do not have a clear picture of your system.
Boiler means it can boil water into steam. In EPlus, a boiler in a plant loop need not run at 100°C to produce steam.
Heating tank is definitely designed not to produce steam.
Heater is the heat source, which can be gas, oil, electric, etc.fired.
Immersion heater, is a heater inserted in the tank.
You can call a coil in a tank a heat exchanger. There are many other names.
Dear Dr.li i say read this i mean i read this in internet , and i m sure your are well in knowing this dear Dr.Li,
in my building there is tank with natural gas heater in tank and has thermostat in its tank that measured hot water temperature in its tank and control heater , that provide hot water to radiator , and also provide hot water to closed space like heat exchanger that there is coil,
From: Tooran T <t.t111ir@xxxxxxxxx>
To: "EnergyPlus_Support@xxxxxxxxxxxxxxx" <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Friday, February 17, 2012 6:59 PM
Subject: Re: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
Dr.Li now i found one thing i dont know is that correct or not
i found that what i mean from boiler is water heater You have both boiler and water heater. If you do not turn off the gas, the water will boil. The DHW tank will never boil.
in my building boiler has burner or heater and has tank and thermometer that measured the water in the tank and if its temperature is greater than 80 then boiler will be on ,..
what i mean from water heater is coil exchanger that one side is connect to hot water and another is connect to cold water from main pipe , then this two tubes exchange Q from hot water and cold water ,...
The coil of the furnace or boiler exchange heat with the DHW tank. The water main provide the water to the shower taps. It is controlled by a float valve to keep the DHW tank full.
but now i dont know from what class object i can simulate this heat exchanger ? This is already done in your IDF as two water loops. The only item need to be verified to make sure that the names of the objects are correct for the DHW system. There are examples in the examples folder. I use the one for solar collector, and for storage tanks.
thanks
From: YuanLu Li <yli006@xxxxxxxxxxx>
To: EnergyPlus_Support <energyplus_support@xxxxxxxxxxxxxxx>
Sent: Friday, February 17, 2012 12:42 AM
Subject: RE: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
T.T
I do not know how you add the schedules, etc.
If you use a text editor, all the manager and schedules can be kept together.
After you have written the manager and the controller, you will immediately follow by the set point schedule by copying the name from the controller to the schedule compact.
Then you will do a check, whether there is a schedule of the same name in the IDF.
If you follow these steps, you will be a good programmer as well.
Using the third party GUI will start your fast and the very difficult to expand your scope later on.
====================
This is my additional remarks for all the users of EPlus. Pay more attention to the IDF program entries and not just having pretity building pictures with many warnings and errors.
Dr. LI.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: t.t111ir@xxxxxxxxx
Date: Thu, 16 Feb 2012 11:24:03 +0000
Subject: Re: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
Dr.Li it is very strange i use setpoint manager for HW plant such as below :
HW supply Outlet Node, !- Loop Temperature Setpoint Node Name
HW Loop Temp Schedule, !- Schedule Name
HW supply Outlet Node; !- Setpoint Node or NodeList Name
Schedule:Compact,
HW Loop Temp Schedule, !- Name
Temperature, !- Schedule Type Limits Name
Through: 12/31, !- Field 1
For: Alldays, !- Field 2
Until: 24:00, 75; !- Field 4
the result are the same when i use
HW supply inlet Node, !- Loop Temperature Setpoint Node Name
i see in winter design day when inlet boiler temperature greater than 75 then it off the boiler in both case.
i dont undrestand why there is no differenc between them
thanks for your attention
From: YuanLu Li <yli006@xxxxxxxxxxx>
To: EnergyPlus_Support <energyplus_support@xxxxxxxxxxxxxxx>
Sent: Wednesday, February 15, 2012 3:16 AM
Subject: RE: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
I do not understand your question or the purpose of the moving of the pump position.
In your PDF diagram, the pump is in the orage coloured pipe, lower temperature return pipe. This is the position in the SVG diagram, and is the recommended branch ordering.
It is possible to move the pump to the demand side inlet, but you should ask the support group, if the simulation fails.
The SVG diagram looks fine, although it is not the usual view, which begins with a pump without a by-pass path.
The Winter operation seems correct.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: t.t111ir@xxxxxxxxx
Date: Tue, 14 Feb 2012 09:16:33 +0000
Subject: Re: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
Dear Dr.Li ,
could you please see the file that i attached it ?
there is pump as first object in supply side in example files of energyplus , i want to know there is problem if i use pump after water heater ?
there is no problem in energyplus simulation that i use bypass with pump ?
thanks
From: YuanLu Li <yli006@xxxxxxxxxxx>
To: EnergyPlus_Support <energyplus_support@xxxxxxxxxxxxxxx>
Sent: Saturday, January 28, 2012 4:08 AM
Subject: RE: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
Algorithm is used to design a software for simulation.
In the earlier version of EPlus, I seem to remember, there was a pump by-pass. The newer version does not seem to have that in the examples of the example file.
The work around is to leave the pump in and reduce the pressure to a smaller value to reflect the temperature difference of the up and down pipes which created a pressure difference.
Simulate it without the by-pass and see how much is the pump power. If it is not significant, simply ignore the pump power. You cannot really stop the pump, as the equation used for simulation requires a pressure difference to circulate the water.
Therefore, instead of using a pump, you will have substitute the equation with one that produces the pressure difference due to temperature difference. This is what I meant by changing the algorithm in simulation.
The
tank can be controlled to the 80 - 65 range without the pump control.
The zone thermotat if is a common one would turn on and off the pump for all the radiators.
In this case you will not have a thermostat control in each room. If the room have different thermal characteristics, the EPlus simulation will show the differences in room temperature.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: t.t111ir@xxxxxxxxx
Date: Fri, 27 Jan 2012 22:09:44 +0000
Subject: Re: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
yes exactly we use pump by bypass mode . what do you mean by different algorithm?
From: YuanLu Li <yli006@xxxxxxxxxxx>
To: EnergyPlus_Support <energyplus_support@xxxxxxxxxxxxxxx>
Sent: Friday, January 27, 2012 10:24 PM
Subject: RE: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
If you turn on and off the pump at 65°C, to implement the pump by pass mode. Again, it is a different algorithm.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: t.t111ir@xxxxxxxxx
Date: Fri, 27 Jan 2012 18:43:08 +0000
Subject: Re: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
i want to :
if inlet water pump > 65C then pump will be off
and if inlet water pump < 65 then pump will be on
for this type of controling can we use two availabilityManager:
one availabilityManager:High temperaturTurnoff :for inlet water pump > 65C then pump will be off .
and another availabilityManager: low temperaturTurnon : for inlet water pump < 65 then pump will be on.
is that right?
thanks
From: Richard Raustad <RRaustad@xxxxxxxxxxxx>
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Sent: Friday, January 27, 2012 8:12 PM
Subject: Re: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
The availability manager actually turns off the pump (or fan for air systems). So any equipment on that loop will be off.
On 1/27/2012 11:25 AM, Tooran T wrote:
thanks Dr.Li ,
i m not good at english so mybye i dont undrestand your word exactly .you say : " If the avilability manager is associated with the heater, it turns off the heater." and
" The size and type of the heater is another matter" what you mean by heater ?is that baseboard heater or water heater?
thank you very much Dr.Li
!- =============
Sizing:Plant,
Boiler Loop, !- Plant or Condenser Loop Name
HEATING, !- Loop Type
80., !- Design Loop Exit Temperature {C}
15; !- Loop Design Temperature Difference {deltaC}
!- ======================
is all you need to enter in the IDF. The size and type of the heater is another matter.
=============================
In control engineering most controller has a built in hysteresis. However, you may not be able to specify it exactly, if it is not designed to be adjustable.
What you are trying to do is to design your own controller.
Dr. Li
To:
energyplus_support@xxxxxxxxxxxxxxxFrom:
yli006@xxxxxxxxxxxDate: Fri, 27 Jan 2012 08:21:27 -0500
Subject: RE: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
If the avilability manager is associated with the heater, it turns off the heater.
If the avilability manager is asspcoated with the tank used side, it turns off the loop supply (pump).
Sensor node need not be in the same loop, but must respond of the change when the control is activated. If the temperature falls below the limit, the control is removed. Back to your thermostat problem. Set-back is not the same as limits.
Dr. Li
To:
EnergyPlus_Support@xxxxxxxxxxxxxxxFrom:
t.t111ir@xxxxxxxxxDate: Fri, 27 Jan 2012 09:36:16 +0000
Subject: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
Dear memebers ,
ref : Document :EngineeringRefrence.pdf -983
"High temperature turn off :
The input object availabilityManager:High temperaturTurnoff is used to turn off a central air system or a plant loop if a sensed node temperature exceeds a temperature limit."
i want to know availabilityManager:High temperaturTurnoff , turn off the plant loop or just the turn off the component ?
for example : i set field :Sensor Node name : at the outlet of boiler .. in this plant loop there is pump and boiler as a component.
then availabilityManager:High temperaturTurnoff turn off boiler or plant loop ?if it turn off the plant loop it means it turned off pump too?
thanks
--
Richard A. Raustad
Senior Research Engineer
Florida Solar Energy Center
University of Central Florida
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Fax: (321) 638-1439 or 1010
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