| Ok, I understand the use of Temperature or Device schedule. Currently, I am trying to figure out the following:
1. The effect of the heat balance algorithm. Because I had my HVAC ON for the entire 24 hrs, but around 2200hrs, my cooling stopped. And I noticed that the Outside Air Temperature was very close to the Inside Air Temp and in fact OAT< Inside Temp. I understand logic behind why the Cooling stopped, but to reason it mathematically, I need to understand the HEAT BALANCE ALGORITHM, is what I think. Kindly give your opinion on this.. Can I find my solution from the ASHRAE handbook to this?
2. When i mention SizingPeriod: some weekday or Summer Design day, and my run period is different, will there be any effect because of the SizingPeriod on my Run Period analysis? I assume not. Correct me if I am wrong
and please elaborate, even if I assumption is true.
3. The dates for the run period when I feed say June 6, which year does it take? I want to know this so that I can know if its a weekday or weeknd. I got confused from my simulation results because when I read the output, the Inside Temp is slightly different from what I expect and then I realize that its following the weekend Schedule for the set points. Also one other thing I wanted to know is, if say my RUN PERIOD is Weekday, however a Holiday( which I assume can be categorized in AllOtherDays), which schedule will set point schedule follow? Is it the Weekday Setpoint schedule or the AllOtherdays schedule?
4. Lastly, coming back to my old question: Say if the set point is 21 deg C and the HVAC is ON. Now th room will cool and the thermostat will read 21 deg C. Why does the HVAC not CUT OFF at this point and instead it is still ON? What I
assumed to see is, once the Thermostat read the set point value, the HVAC is CUT OFF, then room temp rises. Now when the thermostat read 21 + 1 deg C, which is the upper limit, the HVAC will kick ON and cool the room. This cycle continues. How can I achieve this kind of HVAC operation? Can I set a Thermostat Temp range, and mention that once set point is reached HVAC OFF, then when Thermostat reads Set point + minimum 1 deg C, HVAC ON. Since I need to achieve this, I felt that I need a better understanding on the HEAT BALANCE equations. Suggest material or steps I can take to achieve this.
Please explain each point.
Regards,
Aditya --- On Fri, 4/1/11, Jean marais <jeannieboef@xxxxxxxxx> wrote:
From: Jean marais
<jeannieboef@xxxxxxxxx>
Subject: [EnergyPlus_Support] Re: Need some qhuidance on scheduling.
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Date: Friday, April 1, 2011, 1:48 PM
The schedule objects are of different types. They act as constants.. You may have a heating setpoint schedule which describes a temperature or an equipment onoff schedule which describes a state (0 or 1), there are time/date schedules, fractional, ect. There are combinations of these.
HVAC equipment typically has a double heirachy of schedules. The top most is system availability, and the next is operation times. A fan may be available for turning on all of the time (when another set of conditions/equipment asks it to), but is only scheduled to operate at specified times. There are also another even higher control group of objects which can overide schedules.
There's no easy way to start the learning process. Use a simple example and mess with the idf text file is my suggestions.
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Aditya Ravi <adityaravi87@...> wrote:
>
> Hello Pedro,
> Firstly thank you for the quick response. So from what I understand, its the same like setting the conditions for Weekdays or Weekends.Ã?
> Now can I also run my simulation without mentioning a schedule for the SummerDesignDay or WinterDesignDay? So if this is the case, I should not add them in my Sizing Period? Am I correct?
> Also in the HVAC schedule, if I want the HVAC to be ON/OFF at different periods for Summer and Winter respectively, do I create two schedules, or can I do it using one HVAC operating schedule?
> Lastly, I noticed that if we mention the HVAC is ON for a period, then despite the room temperature reaches the set point, the HVAC is still ON? Isn't the HVAC suppose to be cut off and then allow the room temperature to rise up by a degree( Thermostat value) and then again kick ON? Does this have any relation to the heat balance algorithm? And, yes if I want my HVAC to operate like I have mentioned here, then how do I make my modifications? I was suggested that I could use the EMS to do so. However since I am just getting familiarized with the software, I want to first throughly understand the meaning behind every setting. It will be of great help,if you can periodically guide me in this. I am working on my thesis, and I am in search for some guidance in using this software.
> Sincerely,
> Aditya
> --- On Fri, 4/1/11, Pedro Peixeiro <ppeixeiro@...> wrote:
>
> From: Pedro Peixeiro <ppeixeiro@...>
> Subject: Re: [EnergyPlus_Support] Need some qhuidance on scheduling.
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Date: Friday, April 1, 2011, 3:15 AM
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> Ã?
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> Hi Aditya.
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> Setting up a schedule using For:SummerDesignDay or
> For:WinterDesignDay lets you set up HVAC operation for determined
> hours of those types of days. What this basically means is this:
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> using design days is like telling your system "ok, so consider these
> two typical days, one for summer and one for winter. now run my
> model and tell me, for those conditions, what loads do i have and
> show me how my HVAC will perform"
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> setting up a schedule of HVAC operation for those design days is
> further telling the program: "for those typical days, i want my HVAC
> system to be turned on during a set hours of the day and turned off
> during another set hours of the day". This works because a DesignDay
> doesnt have a constant temperature during the 24 hours if you input
> a temperature range in the SizingPeriod:DesignDay object.
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> Example:
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> For: SummerDesignDay
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> Until: 07:00
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> 0
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> Until: 19:00
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> 1
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> Until: 24:00
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> 0
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> If you use this schedule to setup HVAC operation, for your
> SummerDesignDay you will have the HVAC off from 00:00 to 07:00,
> turned on from there up to 19:00 and off again for the remainder of
> the day.
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> Hope this clears your question.
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> Pedro
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> On 31-03-2011 21:38, Aditya Ravi wrote:
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> Ã?
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> Hello,
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> I am new to energyplus and I have a lots of basic
> questions.
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> How do we schedule the HVAC operation for both winter and
> summer. By this I mean, the period for which the HVAC is
> ON/OFF. I am modelling a system for a regular 3 bedroom
> house. I am unable to understand the logic of scheduling
> the moment I see For:WinterDesignDay or SummerDesingDay in
> the HVAC operation schedule. Can you explain the logic to
> me. what do they mean? If possible give me an example.
>
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> Similarly when it comes to the set points, I know how to
> assign values for different times of the day, however, I
> am not clear on the logic behind using For:
> WinterDesignDay or SummerDesignDay.
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> I am planning to use PTAC for for both cooling and
> heating. And its going to be electric and not hot water or
> any other fuel for heating.
>
> Regards,
>
>
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> Aditya
>
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