OpenStudio - Create Air Loops

In this video, we discuss how to create custom air loops for heating, ventilation, and air conditioning systems. We will create a simple heat-vent system and a dual-duct system and connect them to our central plant systems. Transcript: The next task is to install a heat and vent system for the basement area. This basement area also has baseboard hot water heaters in the zones. Go to the thermal zones tab. Fortunately for us, the basement is considered a whole single thermal zone. We only have to worry about this one thermal zone. The basement. Go to the library tab. We will search for baseboard convective water. Drag that into our zone equipment. Now the basement has baseboard hot water heaters as its primary heating source. Now, go up to this chain link icon up here on the edit tab. Click it. Select heating water loop as the heating water source for these baseboard convectors. The rest of this stuff is customizable. Rated average water temperature maybe 160°F (71.1°C). We will just leave the rest of this stuff as default and auto sized. If you do know the specifics, you can change those items there. Let us go to the HVAC systems tab. Go to the plus at the top. We will add a new...well we can do this warm air gas-fired furnace. We will add this to the model. It comes in as all prepared for us. However, we are not going to use a gas furnace for heating. We are going to use a hot water heating coil. So, we will delete that. Go to the library tab. We need to search for coil heating water. Hot water heating coil. We will drop this in here. We can select the heating water coil. We will just call this HV for heat and vent. Again, for the heating water coil, you go up to the the chain link button on the edit tab. Click it. We need to link this heating water coil to our heating water loop. Go back to the edit properties tab. We can leave all the rest of this stuff at its default values. I recall this system was a constant volume system. We will just leave this as a constant volume fan. We will just rename all these things. This is going to be a HV. I will just call it HV-1. The airflow rate for this was 3,000 cfm (5,100 m3/h). Design outdoor air flow rate. I do not think I have that information. We will just leave all the rest of this as a default for now. Design supply air temperature was 105°F (40.6°C). Well let us see. This is for sizing. We probably want to size the coil for 100% outdoor air in heating and cooling. That would be the sizing of the system. We can just leave all the rest of this stuff as default for now. You will note that it already has a air terminal (constant volume diffuser) on the demand side. If you know what size any of this stuff is, you can always go to the edit tab and edit those. We are just going to assign the zones. We will click the splitter right here. We only have one zone, so we are going to click the basement (zone). Add that basement zone to the HV system. Then, as discussed before, this is a constant volume system, so it is good to have a bypass duct... oh...let us see... I am not sure if a bypass duct is necessary...but...nope It will not let us do that. Yeah...that would be only for... I believe that would be only for VAV systems. There might be some additional settings under your air loop system for bypass on constant volume systems. That is it for our heat vent system. Now, we need to add the dual duct air handlers. Go up to the plus button. This time we will scroll down to a dual duct air loop. Click "add to model". We will call this AHU1. We can leave this auto sized for now. The central heating maximum system airflow ratio. Let us see...I think for this system it was 50%. What else. Design supply air temperature. This was 105°F (40.6°C). Yep. The rest of this stuff we can leave as default. Click save. Next we need to install an outdoor air system. Air loop hvac outdoor air system. Let us see, I have a bunch of stuff in here from a library connection. Let us go back to default libraries and we will just remove this. Click OK. That way we do not have that cluttering up our list. Let us go back to the air loop. We need to add an air loop hvac outdoor air system. Drop that there...call it AHU1 Outdoor Air System. We also need to add in a an air-to-air heat exchanger. Air-to-air. Here we go. You can choose what type of heat exchanger. I believe we have an energy recovery wheel on this system. We will just drop this in between here. One energy recovery heat exchanger. We also have a fan. An exhaust fan. Powered exhaust fan; variable speed. Drop this in here. Let us see. I am trying to remember if this fan had inlet guide vanes. We will get into those details later. Let us go to outdoor air. This was 17,500 cfm (29,730 m3/h). Maximum flow rate was 150,000 (254,850 m3/h). Ok,so minimum was 17,500 maximum was 150,000. Economizer control type: fixed dry bulb. That should be it for the outside air system. … Full Transcript: https://www.helix-engineers.net/technical-articles