Dear Dr.Li
thankd for your answering ,
yes i undrestand about bypass pump , thanks for your useful describing , but i dont undrestand how loop temperature setpoint control the loop? nad how i can control burner of boiler for example turn on the burner of boiler when ever outlet temperature of water from boiler is greater than 80C , and turn of the nutural gas flow of burner boiler when ever outler temperature of water from boiler is less than 75C?
How to turn the radiators off? Do you know how it is done? You were only simulating during the Winter months of the weather file.
i use Availability Schedule for radiators that radiator will be off in summer :
winteron, !- Name
Any Number, !- Schedule Type Limits Name
Through: 3/31, !- Field 1
for:alldays, !- Field 2
until: 24:00, 1, !- Field 4
through: 9/30, !- Field 5
for: alldays, !- Field 6
until: 24:00, 0, !- Field 8
through:
12/31, !- Field 9
for: alldays, !- Field 10
until: 24:00, 1; !- Field 12
but i have problem i dont know when energyplus turn on/off the boiler ?
i want to off the natural gas of burner of boiler when its outler water temperature from the boiler is greater than 80C, and on the boiler when outler temperature less that 75C (5C is deadband )
if outler water temperature of boiler > 80 then off the burner of boiler
and when outler water temperature of boiler < 75 then on the burner of boiler , i dont know how i can control the burner of boiler like that ?!
Dr.Li could you please desribe it for me how setpoint temperature control the plant?
when i run the idf for sizingperiod day i see in variable output file excel winter design day is repeated for 6-7 times like below :
i dont undrestant this repeat? is this warm up? it repeats until convergence reaches?
01/15 00:10:00
01/15 00:20:00
01/15 00:30:00
01/15 00:40:00
01/15 00:50:00
.......
01/15 24:00:00
01/15 00:10:00
01/15 00:20:00
01/15 00:30:00
01/15 00:40:00
01/15 00:50:00
.......
01/15 24:00:00
.
.
.
thanks Dr.Li ,
From: YuanLu Li <yli006@xxxxxxxxxxx>
To: EnergyPlus_Support <energyplus_support@xxxxxxxxxxxxxxx>
Sent: Wednesday, February 15, 2012 9:23 PM
Subject: RE: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
Simulation will do whatever you ask the program to do.
It is not necessary to provide a by-pass. You can use a pump which has a low head to simulate the natural flow.
You can look at the .rdd and see what is available. If there is a flow rate through the bypass in the output variable, you can monitor that.
If a branch or component has an available schedule, it can be scheduled. Scheduling need not be automatic. If your caretaker turns on and off the pump manually every morning after starting the furnace, you will schedule both these activities.
The house hold thermostat has mercury switch module with two contacts mounted on a temperature sensing element. There is also a fan speed control (off, 1,2,3), heat/cool control, and a thermometer. All these are simulated separately, as sensor, controller or actuator, and selectors.
======
You can use
the pump mass flow rate variable to show that the pump is working. This is monitoring process. Scheduling is a control process. Sense and then actuate is a controller manager action.
=====================
If your are worried about the power consumption, simply reduce the head. The circulation pump is not a large element, unless you need to lift the water to a very high level into an open tank.
When all the radiators are turned off in Summer, the pump will only pumping the DHW heater. You can sense the DHW temperature and force the pump on again, if necessary.
===================
How to turn the radiators off? Do you know how it is done? You were only simulating during the Winter months of the weather file.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: t.t111ir@xxxxxxxxx
Date: Wed, 15 Feb 2012 10:46:39 +0000
Subject: Re: [EnergyPlus_Support] availabilityManager:High temperaturTurnoff
can i use pump flow rate schedule to show some times pump is out of work and water flows in bypass branch ?
From: Tooran T <t.t111ir@xxxxxxxxx>
To: "EnergyPlus_Support@xxxxxxxxxxxxxxx" <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Wednesday, February 15, 2012 10:16 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.
use bypass with pump , in example files of energyplus i see it use boiler branch with bypass , but in my idef i use pump branch with bypass branch .
in summer or some times of the year that produces the pressure difference due to temperature difference ,(natural circulating with out need pump )
we use bypass mode and pump is out of the work , how can i show this in simulation in energyplus ?( i want to say use bypass branch instead of pump in summer )
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in OBJECTS IN CLASS: WATERHEATER:MIXED
WaterHeater:Mixed,
Indirect Water Heater, !- Name
AUTOSIZE, !- Tank Volume {m3}
water heater Setpoint Temperature Schedule, !- Setpoint Temperature Schedule Name
field: Setpoint Temperature , determines when heater of the water heater will be on and off ,is that right?
but in ALL OBJECTS IN CLASS: BOILER:HOTWATER, there is no Setpoint Temperature Schedule field to determines when burner of boiler will be on and off , how can i control the burner of boiler?does setpoint temperature in pLant loop(hot water plant loop) controls burner of boiler ?
the setpoint temperature for plant loops it means it controls the whole plant (pump , boiler )?