Hello everyone,

I just developed a primary-secondary chilled water system to provided the chilled water for multiple ZoneHVAC:FourPipeFanCoil that are served as Zone Equipments in thermal zones. The current configuration of the system is like the figure as below and i also attach my osm file here for you guys to download https://drive.google.com/file/d/1bjjuAndM56xUBT9ycc7zqOsZW1eQJk5l/view?usp=sharing : .

My question is how to configure my system according to the following figure.

I want to use three pumps to serve the ZoneHVAC:FourPipeFanCoil that are distributed in different parts of a building. For example, the fan coils in 1st-3rd floors will be served by pump 1, and fan coils in 4th-7th floors will be served by pump 2 and fan coils in other floors will be served by pump 3. This configuration is very common in real engineering project, but i did not find a way to add a parallel branch for the fan coils and pumps. I read the Engineering Reference of Energyplus and it seems that only one splitter and mixer is allowed for the supply or demand half loop. Is anyone has an idea on how to handle this issue. Thank you Very much!

Hello everyone,

everone, I just developed a new primary-secondary chilled water system to provided the chilled water for multiple ZoneHVAC:FourPipeFanCoil that are served as Zone Equipments in thermal zones. The current configuration of the system is like the figure I set all input parameters for the objects ofChiller:Electric EIR, Pump:Constant Speed,Pump:Variable Speed and ZoneHVAC:FourPipeFanCoil as below and autosized and ran the simulation. Based on the simulation results, i got some questions to ask you guys. By the way, i also attach attche my osm file here for you guys to download https://drive.google.com/file/d/1bjjuAndM56xUBT9ycc7zqOsZW1eQJk5l/view?usp=sharing : .

My question is how to configure Qustion 1： I opened the eplusout.sqlfile to check the the sizing data of the Coil:Cooling:water through the ComponentSizes table. I was confused that why the "Design Size Design Inlet Water Temperature" was 82oC. I tried to manually set the design inlet water temperature as 6oC, but the autosizing still used the value of 82oC. I have checked my system according to the following figure.

I want to use three pumps to serve the ZoneHVAC:FourPipeFanCoil that are distributed in different parts of a building. For example, the fan coils in 1st-3rd floors will be served by pump 1, and fan coils in 4th-7th floors will be served by pump 2 and fan coils in other floors will be served by pump 3. This configuration is very common in real engineering project, but i osm file settings and did not find a way to add a parallel branch reason.Here is a snapshot of component sizing results fom the database:

Question2: i am using multipleZoneHVAC:FourPipeFanCoilto serve a single zone. but i did not find any object in openstudio to let me set the load distribution over the multiple ZoneHVAC:FourPipeFanCoilobjects. That is i have no idea about how the load is distributed over the several Coil:Cooling:water objects for the fan coils and pumps. I read the Engineering Reference capacity sizing.

Question3: I am setting up the Common Pipe Simulation, but there are two options to let me choose: "CommonPipe" and "TwoWayCommonPipe". From the Energyplus documents i learned that the TwoWayCommonPipe soption can let me make adjustment on the temperature and flow compared to commonpipe setting, but i am still confused about the difference between these two options.

Question4: what is the purpose of Energyplus and it seems using a bypass for the primary water loop? i noticed the flow rate through the bypass always remained zero and i thought the bypass was only used when the chiller was sheduled off so that only one splitter and mixer is allowed for the supply or demand half loop. Is anyone has an idea on how to handle this issue. Thank you Very much!the water from the pump can go though it. I am noy sure my understanding is right is not?

Hello everone, I just developed a new primary-secondary chilled water system to provided the chilled water for multiple ZoneHVAC:FourPipeFanCoil that are served as Zone Equipments in thermal zones. I set all input parameters for the objects ofChiller:Electric EIR, Pump:Constant Speed,Pump:Variable Speed and ZoneHVAC:FourPipeFanCoil as autosized and ran the simulation. Based on the simulation results, i got some questions to ask you guys. By the way, i also attche my osm file here for you to download https://drive.google.com/file/d/1bjjuAndM56xUBT9ycc7zqOsZW1eQJk5l/view?usp=sharing :

Qustion 1： I opened the eplusout.sqlfile to check the the sizing data of the Coil:Cooling:water through the ComponentSizes table. I was confused that why the "Design Size Design Inlet Water Temperature" was 82oC. I tried to manually set the design inlet water temperature as 6oC, but the autosizing still used the value of 82oC. I have checked my osm file settings and did not find a reason.Here is a snapshot of component sizing results fom the database:

Question2: i am using multipleZoneHVAC:FourPipeFanCoilto serve a single zone. but i did not find any object in openstudio to let me set the load distribution over the multiple ZoneHVAC:FourPipeFanCoilobjects. That is i have no idea about how the load is distributed over the several Coil:Cooling:water objects for capacity sizing.

Question3: I am setting up the Common Pipe Simulation, but there are two options to let me choose: "CommonPipe" and "TwoWayCommonPipe". From the Energyplus documents i learned that the TwoWayCommonPipe soption can let me make adjustment on the temperature and flow compared to commonpipe setting, but i am still confused about the difference between these two options.

Question4: what is the purpose of using a bypass for the primary water loop? i noticed the flow rate through the bypass always remained zero and i thought the bypass was only used when the chiller was sheduled off so that the water from the pump can go though it. I am noy sure my understanding is right is not?

Hello everone, I just developed a new primary-secondary chilled water system to provided the chilled water for multiple ZoneHVAC:FourPipeFanCoil that are served as Zone Equipments in thermal zones. I set all input parameters for the objects ofChiller:Electric EIR, Pump:Constant Speed,Pump:Variable Speed and ZoneHVAC:FourPipeFanCoil as autosized and ran the simulation. Based on the simulation results, i got some questions question to ask you guys. By the way, i also attche my osm file here for you to download https://drive.google.com/file/d/1bjjuAndM56xUBT9ycc7zqOsZW1eQJk5l/view?usp=sharing :

Qustion 1： I opened the eplusout.sqlfile to check the the sizing data of the Coil:Cooling:water through the ComponentSizes table. I was confused that why the "Design Size Design Inlet Water Temperature" was 82oC. I tried to manually set the design inlet water temperature as 6oC, but the autosizing still used the value of 82oC. I have checked my osm file settings and did not find a reason.Here is a snapshot of component sizing results fom the database:

Question2: i am using multipleZoneHVAC:FourPipeFanCoilto serve a single zone. but i did not find any object in openstudio to let me set the load distribution over the multiple ZoneHVAC:FourPipeFanCoilobjects. That is i have no idea about how the load is distributed over the several Coil:Cooling:water objects for capacity sizing.

Question3: I am setting up the Common Pipe Simulation, but there are two options to let me choose: "CommonPipe" and "TwoWayCommonPipe". From the Energyplus documents i learned that the TwoWayCommonPipe soption can let me make adjustment on the temperature and flow compared to commonpipe setting, but i am still confused about the difference between these two options.

Question4: what is the purpose of using a bypass for the primary water loop? i noticed the flow rate through the bypass always remained zero and i thought the bypass was only used when the chiller was sheduled off so that the water from the pump can go though it. I am noy sure my understanding is right is not?

Hello everone, I just developed a new primary-secondary chilled water system to provided the chilled water for multiple ZoneHVAC:FourPipeFanCoil that are served as Zone Equipments in thermal zones. I set all input parameters for the objects ofChiller:Electric EIR, Pump:Constant Speed,Pump:Variable Speed and ZoneHVAC:FourPipeFanCoil as autosized and ran the simulation. Based on the simulation results, i got some question to ask you guys. By the way, i also attche my osm file here for you to download :

Qustion 1： I opened the eplusout.sqlfile to check the the sizing data of the Coil:Cooling:water through the ComponentSizes table. I was confused that why the "Design Size Design Inlet Water Temperature" was 82oC. I tried to manually set the design inlet water temperature as 6oC, but the autosizing still used the value of 82oC. I have checked my osm file settings and did not find a reason.Here is a snapshot of component sizing results fom the database:

Question2: i am using multipleZoneHVAC:FourPipeFanCoilto serve a single zone. but i did not find any object in openstudio to let me set the load distribution over the multiple ZoneHVAC:FourPipeFanCoilobjects. That is i have no idea about how the load is distributed over the several Coil:Cooling:water objects for capacity sizing.

Question3: I am setting up the Common Pipe Simulation, but there are two options to let me choose: "CommonPipe" and "TwoWayCommonPipe". From the Energyplus documents i learned that the TwoWayCommonPipe soption can let me make adjustment on the temperature and flow compared to commonpipe setting, but i am still confused about the difference between these two options.

Question4: what is the purpose of using a bypass for the primary water loop? i noticed the flow rate through the bypass always remained zero and i thought the bypass was only used when the chiller was sheduled off so that the water from the pump can go though it. I am noy sure my understanding is right is not?

Hello everone, I just developed a new primary-secondary chilled water system to provided the chilled water for multiple ZoneHVAC:FourPipeFanCoil that are served as Zone Equipments in thermal zones. I set all input parameters for the objects ofChiller:Electric EIR, Pump:Constant Speed,Pump:Variable Speed and ZoneHVAC:FourPipeFanCoil as autosized and ran the simulation. Based on the simulation results, i got some question to ask you guys. By the way, i also attche my osm file here for you to download : for checking my problems:

Qustion 1： I opened the eplusout.sqlfile to check the the sizing data of the Coil:Cooling:water through the ComponentSizes table. I was confused that why the "Design Size Design Inlet Water Temperature" was 82oC. I tried to manually set the design inlet water temperature as 6oC, but the autosizing still used the value of 82oC. I have checked my osm file settings and did not find a reason.Here is a snapshot of component sizing results fom the database:

Question2: i am using multipleZoneHVAC:FourPipeFanCoilto serve a single zone. but i did not find any object in openstudio to let me set the load distribution over the multiple ZoneHVAC:FourPipeFanCoilobjects. That is i have no idea about how the load is distributed over the several Coil:Cooling:water objects for capacity sizing.

Question3: I am setting up the Common Pipe Simulation, but there are two options to let me choose: "CommonPipe" and "TwoWayCommonPipe". From the Energyplus documents i learned that the TwoWayCommonPipe soption can let me make adjustment on the temperature and flow compared to commonpipe setting, but i am still confused about the difference between these two options.

Question4: what is the purpose of using a bypass for the primary water loop? i noticed the flow rate through the bypass always remained zero and i thought the bypass was only used when the chiller was sheduled off so that the water from the pump can go though it. I am noy sure my understanding is right is not?