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2024-03-04 07:29:38 -0500 | received badge | ● Popular Question (source) |
2023-10-14 06:05:32 -0500 | marked best answer | Baseline system 4 performance I'm modeling a baseline building system 4 with 90.1-2007. I do not understand what performance to set. I've been looking into table 6.8.1B, where you have to choose between the source, the type and the power. I chose Air condensed single package system. Is 6.8.1B the right table? Then I have to choose the performance based on the size of the coil: I find the range 19 kW to 40, 40 kW to 70 kW or more than 70 kW. What if the size is lower than 19 kW? What cop should I use? The only size below 19 kW is reported as a SCOP (not cop). |
2023-02-15 12:30:46 -0500 | received badge | ● Popular Question (source) |
2022-05-19 09:40:43 -0500 | marked best answer | LEED Baseline Building: G3.1.2.9 Hi, I have a doubt about System Fan Power with System 8. G3.1.2.9 says: System fan electrical power for supply, return, exhaust, and relief (excluding power to fanpowered VAV boxes) shall be calculated using the following formulas:.... Moreover, G3.1.2.8 says: If return or relief fans are specified in the proposed design, the baseline building design shall also be modeled with fans serving the same functions and sized for the baseline system supply fan air quantity less the minimum outdoor air, or 90% of the supply fan air quantity, whichever is larger. Therefore, I understood to apply the G3.1.2.9 method to the supply fan with 100% of design flow rate and to apply it again to the return fan with 90% of design flow (or the supply minus the outdoor air). So I get two different powers to apply to these fans. My way of thinking appears to be wrong since the power is intended to be the sum of the supply and return fan. This can be noticed also from the 1.4 table. Can someone make it clear? If the second method is the correct one: how do I redistribute this power between supply and return fans? Thank you |
2022-05-04 06:43:05 -0500 | marked best answer | Weather file altitude VS building altitude (EnergyPlus) If the weather file altitude and the building altitude (Site:Location -> Elevation) differs, does E+ automatically apply a correction? In my case, the objects Site:WeatherStation and Site:HeightVariation are blank. From what I can read in the documentation, the correction (if set) is applied to altitude variations within the model, for example between ground floor and the attic of a high building. Is it correct? |
2022-02-21 02:48:13 -0500 | commented answer | Run EnergyPlus in Matlab Sorry I can't help, I solved using python |
2022-01-20 16:49:57 -0500 | marked best answer | precipitation: EPW vs Site:Precipitation Hi, I'm using EnergyPlus. My question is straightforward: between EPW and the object Site:Precipitation data, which one has the priority? Does the Site:Precipitation object overwrite the EPW data? Thank you |
2021-11-16 01:22:47 -0500 | marked best answer | Water condenser low temperature, chiller heat recovery Hi, I'm trying to model a chiller with heat recovery, for DHW purposes. I'm using a Chiller:Electric:EIR connected to a WaterHeater:Mixed. The model is running but I get a very low water temperature from the chiller condenser. Basically the water going into the tank water heater is decreasing its temperature since the inlet water temperature goes from 30°C to 20°C. How can I get an higher temperature from the chiller condenser? Did anyone have the same issue? I found something here: https://unmethours.com/question/19434... Thank you in advance |
2021-08-02 11:04:17 -0500 | received badge | ● Self-Learner (source) |
2021-05-30 05:14:52 -0500 | received badge | ● Popular Question (source) |
2021-05-12 16:28:25 -0500 | marked best answer | Run EnergyPlus in Matlab I'm trying to run EnergyPlus in Matlab. I found mle+ but I could only find guides for the GUI. Since I have to run many simulations with data previously calculated in a Matlab script, it could be easier to run E+ directly inside a loop statement. I found out how to do in python (https://unmethours.com/question/22157...) but I couldn't find it in Matlab. Thank you! |
2021-03-09 02:04:56 -0500 | received badge | ● Popular Question (source) |
2020-08-26 16:59:19 -0500 | marked best answer | Elements - Normal Solar versus Direct Normal Radiation I'm trying to use Element software to create new weather files. Now i have some doubts about the outputs: it gives me back the "Normal Solar" instead of the "Direct normal Radiation" that E+ should demand. Am I wrong? I couldn't find a way to force this variable because it's related to the "Global solar" and to the "Diffuse solar" through an equation. Therefore I can't set all three variables: one is auto-calculated. |
2020-03-27 20:19:49 -0500 | received badge | ● Popular Question (source) |
2020-01-29 07:56:12 -0500 | commented question | Optical depths for the ASHRAE Clear Sky Model Do you need to calculate your own coefficients (from measurements) or you just do not know where to find them? |
2020-01-27 18:42:25 -0500 | marked best answer | Python Eppy, readhtml table Hi, I'm trying to use eppy to read EnergyPlus html tables. When I type (as explained here http://pythonhosted.org/eppy/Outputs_... ): I get the following error: "ModuleNotFoundError: No module named 'eppy.results'". I've read here (https://github.com/santoshphilip/eppy...) there's an issue about it: as advised, I installed it with Anaconda prompt: The installation was successful but I get the same error in Python, nothing changed. Has anyone solved this problem? Could I use another method to read this tables? |
2019-10-25 01:43:30 -0500 | commented question | How to set different working directories for parallel simulations? I know it is not what you are looking for, but you could run two different python instances pointing two different folde |
2019-10-04 09:14:13 -0500 | commented answer | Energyplus, Design day : date and solar radiation @eru You are right, if you don't change the air temperatures you could get an oversized result. To solve it, you can use |
2019-10-04 09:13:27 -0500 | commented answer | Energyplus, Design day : date and solar radiation @eru You are right, if you don't change the air temperatures you could get an oversized result. To solve it, you can use |
2019-10-01 12:56:18 -0500 | commented answer | Energyplus, Design day : date and solar radiation If you have no idea and if it does not take too long, add 12 "SizingPeriod:DesignDay" objects, one for each month |
2019-09-27 04:21:26 -0500 | edited answer | Energyplus, Design day : date and solar radiation The solar radiation is not influenced by the weather file: of course it is right to take a look into the weather data to |
2019-09-27 04:20:00 -0500 | edited answer | Energyplus, Design day : date and solar radiation The solar radiation is not influenced by the weather file: of course it is right to take a look into the weather data to |
2019-09-27 01:47:11 -0500 | answered a question | Energyplus, Design day : date and solar radiation The solar radiation is not influenced by the weather file: of course it is right to take a look into the weather data to |
2019-09-25 08:52:31 -0500 | commented question | Warmest vs WarmestTemperatureFlow SetpointManager: DCV I could not replicate the error in a test model: everything looks right during the test. I guess it is something related |
2019-09-23 13:45:02 -0500 | asked a question | Warmest vs WarmestTemperatureFlow SetpointManager: DCV Warmest vs WarmestTemperatureFlow SetpointManager: DCV My question is related to these specific answers: https://unmetho |
2019-09-05 02:33:26 -0500 | marked best answer | Condenser water flow rate with EMS: EnergyPlus My question is related to this issue (https://unmethours.com/question/35540... ticket: https://github.com/NREL/EnergyPlus/is...) where the condenser pump is not working as expected. Is there a way to control the condenser water flow rate with an EMS program? I guess it could be done using the "Chiller Condenser Heat Transfer Rate [W]" output as sensor and a "SetpointManager:Scheduled" as actuator. Unfortunately it is not possible since the condenser loop requires a temperature setpoint. Is there another way? |
2019-09-05 02:32:36 -0500 | edited answer | Condenser water flow rate with EMS: EnergyPlus Following the previous answer by Julien Marrec I tried the following: I used the example file "CoolingTower_TwoSpeed" |
2019-09-05 02:30:32 -0500 | answered a question | Condenser water flow rate with EMS: EnergyPlus Following the previous answer by Julien Marrec I tried the following: I used the example file "CoolingTower_TwoSpeed" R |
2019-09-05 02:04:50 -0500 | commented answer | Condenser water flow rate with EMS: EnergyPlus I think it works....! Thanks a lot, I'll add the results in another answer below. |
2019-09-05 02:04:33 -0500 | commented answer | Condenser water flow rate with EMS: EnergyPlus I think it works....! Thanks a lot, I'll add the results in another answer below. |
2019-08-30 05:37:28 -0500 | commented answer | Condenser water flow rate with EMS: EnergyPlus uh yes, those equations are exactly what I was thinking about: the pump actuator is what I was missing. I guess I will t |
2019-08-30 05:36:52 -0500 | commented answer | Condenser water flow rate with EMS: EnergyPlus uh yes, those equations are exactly what I was thinking about: the pump actuator is what I was missing. I guess I will t |
2019-08-30 05:36:29 -0500 | commented answer | Condenser water flow rate with EMS: EnergyPlus uh yes, that equations are exactly what I was thinking about: the pump actuator is what I was missing. I guess I will tr |
2019-08-26 08:04:25 -0500 | asked a question | Condenser water flow rate with EMS: EnergyPlus Condenser water flow rate with EMS: EnergyPlus My question is related to this issue (https://unmethours.com/question/355 |
2019-08-26 07:52:11 -0500 | commented answer | Baseline HVAC system Yes you are right, my answer was related to the 90.1-2007 that (if I'm not wrong) do not contain any exception based on |
2019-08-22 03:48:04 -0500 | answered a question | Baseline HVAC system Table G3.1.1A states that if your source is electric (proposed) you have to chose one option in the last column, therefo |
2019-08-12 11:12:54 -0500 | commented question | Water cooling coil design inputs Same here: all the coils, fan coil and fans are "as designed" and not "autosize" |
2019-05-06 10:03:01 -0500 | marked best answer | LEED Baseline G3.1.2.1: EER and COP with fan energy Hi, I'm trying to break down the fan power from the System 4 performance. I've read this answer: https://unmethours.com/question/27720... I use the Ashrae 2007 SI edition and if I use the following data (as an example): Cooling 39 kW (autosize) so I consider a power of 40 kW that is 136486 btu/h Considering the table 6.8.1B I have a COP of 3.16 (as of 1/1/2010) I apply the formula: 7.8410^-8EERQ+0.338EER = 7.8410^-83.16136486+0.3383.16 = 1.10 So I get a COP of 1,10 that seems very low. Is there a mistake? Is it correct to level up the cooling power to the higher interval (39 kW to 40 kW)? |
2019-05-01 13:20:03 -0500 | marked best answer | VRF with hot water generation, heat exchanger Hi, I need to model a VRF system with a so called "Hydro Box". It is a plate heat exchanger that allow to generate hot water that can be used both for heating demand (ie heated floor) and for DHW demand. Therefore the system can produce heating with hot water AND with direct expansion coils (split). I specify that this approach is considered in heating mode, so it's not related to a heat recovery during cooling (that I know it can be modeled). So my question is: is there a way to model a condenser based on a "refrigerant to water heat exchanger"? Thank you |
2019-04-25 08:44:28 -0500 | commented answer | Appendix G Cooling Tower, System 8 Thanks, it works. I'm only concerned about one thing, in the html I get a cooling tower capacity that is almost 50% of t |