System 4 Script Preview
First we will open a system. We always oversize the cooling coil. We size it at 1.15. We set the supply temperature to 55, a delta T of 20. Then we edit heating. Heating is 125% or 1.25. The heating supply temperature doesn't define the airflow. So let's just right click and restore default. 105 is reasonable. And we can go back to the basics tab. As we said, the system type is Packaged Single Zone. The remaining details depend on system size.
Let's show you what we mean and quickly simulate. Let it run and view detailed simulation. Open the Sim file. Let it load. And let's look at the SV-A report. There are two or three important numbers. We find the cooling and heating capacity. And supply air cfm. Just note this for later. We will show you that one more time. View the detailed sim file. And navigate to The SV-A Report. eQUEST calculates capacities for each system. We are going to use this later.
Let's go back to our model. The specifics of each system depend on the size of each system. And then we use Table 6.8.1b from ASHRAE 90.1. The table varies with different years. In all standards, it takes the equipment type by size category and heating type and provides a baseline efficiency. Here we have 10.8 EER, For Non-Electric resistance heatpumps sized between 65 and 135 KBTU. Our model showed 81 KBTU. So cooling is at 10.8 EER. And we get heating efficiency from the next page. 3.3 COP for this size range. If you don't know, choose the higher COP. Let's review this.
When your baseline is setup, calculate your baseline system sizes. Open Table 6.8.1.b Equipment type Air cooled. Find the matching size. In our case, 81 KBTU is between 65 and 135. The heating section is based on your proposed. The proposed had no electric resistance heat. So the type is All other. The baseline cooling efficiency is 10.8 EER. And for heating 3.3 COP. For baseline heating efficiency.
Going back into our model. We need to update each system. Let's start with the first. First, set the cooling EER. Under the cooling tab Unitary Power eQUEST uses EIR, which is the inverse. 1.15 for all cooling coils. Here's a trick: Edit the user default and enter 1.15. It will update all the green values to blue. Same thing for heating capacity. Except we use 1.25 per 90.1. Update the default. There it is. Most of these changes are identical for each system, except the heating and cooling efficiency.
Let's go to heating Unitary power. We can see the .303 from earlier. The fan power also varies. We entered placeholders before. Based on 2697 CFM. If we update to 1677. We get .000835 KW/CFM. Which is a slight change. This was for System G.N3. Let's update G.N3. Then look at other systems. Looking through the SIM file. 1677 CFM. 2706 CFM. 3323 CFM. Most of these are similar. I'm making a point here.
Let's enter 3323. And we get .000801. The same as when earlier. So most of these will be the same, except for two zones. T.N13 has 1739 CFM. This is up to 3456. So let's try that. And we get .000801 again. It appears the minimum KW/CFM for this calculation. Let's look at the other North Zone. Enter 1739. And we get .0008348 again. Copy that. Let's compare it to 1677 again. And we get a similar value. So we update two systems. G.N3 .000834. And T.N13 at the same.
There are a few things to do yet. We have to set the fan night cycle control. Set the user default. Cycle on Any. Let's redo that. There we go. We still have to set the EIR for each system. Most of them will be the same. So we will just copy the value from earlier to all of them. We do the same for Heating EIR. Let's verify capacities. The EIR is based on the cooling capacity. 88 KBTU was between 65 and 135. So is 129. This system is smaller. Less than 65 KBTU. This is similar. So is this. And this.
What do we enter for the 65 KBTU system? We see a 13.00 SEER and 7.7 HSPF. Take 3.412/7.7 to get .443. Find the conversion for SEER to EER. So we take 3.142 divided by 13 SEER. Divide by .875 to convert to EER and get .3000 EIR. Update the two North Zones. And we just need to update heating. One other thing. We need to set the sizing ratio to 1 for each system. Because we oversized the cooling and heating already.