First off I looked at what ESI has done, and they are almost all the way there. They did an amazing job. I think we all got hung up on override points, so I suggest we table overrides for now, and we nail down everything else. I also thought that I would contribute some diagrams that might help us nail down where all the tags are. So here is a diagram that might show an easy Chiller Plant.

Ok let's take a look at the points in this diagram, and let's take a stab at tagging them. Here is a list of the points. They purposely are named funny, so that we can point out that point naming doesn't matter anymore, it's really all about what tags you put on the points. This is what haystack is all about.

- CHWR Flow
- CHWS Flow
- CHWP Status
- CHWP Command
- CHWST
- CHWRT
- CHWS Valve Cmd
- Chiller

Now let's try and put tags on those as well:

- CHWR Flow: water discharge flow chilledLoop main sensor primary
- CHWS Flow: water return flow chilledLoop main sensor primary
- CHWP Status: chilledLoop pump status water sensor primary
- CHWP Command: chilledLoop pump water cmd primary
- CHWST:chilledLoop water discharge temp sensor localChlr
- CHWRT:chilledLoop water discharge temp sensor localChlr
- CHWS Valve Cmd: chilledLoop water valve localChlr
- Chiller:chiller status sensor localChlr chilledLoop

I put something in there called localChlr, cause it would be nice to know if the devices are installed at the chiller itself. Many times in a central plant you have multiple sensors that are in the same pipe. It's nice to know if those sensors are at the chiller or remote. I'm sure that's a bad name, so if you agree with the idea, then let's come up with a better name for that.

chilledLoop would tell us that it's on the chilled water side, as opposed to the condenser side.

primary tag would tell us that the device/sensors/cmds are on the primary loop of the central plant, as opposed to the secondary loop.

So in summary. a Chiller Plant can have a primary and secondary loop. Which we can just have a tag called primary, or secondary. You also will either be on the condenser water side or the chilled water side. Which I propose we call it chilledLoop, or condenserLoop. I also suggest that if points are local to a piece of equipment like a chiller/boiler/tower. That we have another tag called localChlr, or localTower

Again, I'm just trying to get a starting point here, so hopefully this will get us headed in the right direction. I'm sure I made a billion mistakes like I normally do :} I am drinking a red bull right now and not wine

I think our push this summer to work on the ESI tags definitely got derailed on the override issues (well that and it was summer :) So I agree lets table the override and make some progress on other fronts.

I discussed with Jason a bit, and I think his proposal wasn't really framed with the existing tags and the discussion we have already had in topic 35.

First off, based on that discussion we have a final decision to renamed the condensed tag to condenser.

Also part of that discussion was tags for primary and secondary loops, as well as potentially tags for common and dedicated pumps and valves. This needs more discussion I think, and I think Jason is going to add some more diagrams for us to use. To a large extent, I think what we define is based on how far we want to model the piping system.

Also a key part of this discussion is whether to model valves and pumps as points or equipment in their own right. This is also right in line with what we started discussing in the ESI work with VFD fans. I will admit, this seems like a tough one. In simple cases, it is nice to model fan, pumps and valves as just a point. But there is definitely more complex models where they are really better off modeled as a sub equip. I've started thinking maybe we need a new abstraction concept to handle this case elegantly.

OK so I talked offline with Brian, and a couple other people and realized that some of the things I presented above were actually already solved. So let's make it real easy.

- 1: I think we all agreed to renamed **condensed** to **condenser**.
- 2: I think we also agreed that **primary**, and **secondary** work best.

Now let's tackle pumps. Alper had a good idea to have a pump that can either be dedicated, or common. In the below diagram you will see that the Chilled Water Pumps are actually dedicated per chiller, and the Condenser Pumps are actually common to the Cooling Tower. It might be a bad example, cause we only show 1 Cooling tower, but I think it still works. So one of the questions is. If you have 2 pumps but they both goto the same Cooling Tower or CHiller, should they be dedicated or Common?

Chiller Plant Diagram 2

So here are the tags I propose for pumps.

- CHWP1: chilled water dedicated primary pump
- CDWP1: condenser water common pump

Ok let's look at one more Plant so we can make sure we understand it all.

Chiller Plant Diagram 3

I named the pumps SP1 and PP1, which is Secondary Pump, and Primary Pump. This plant is a primary secondary system. The secondary pumps have VFDs, and typically ramp up and down on Pressure, or GPM. Let's take a stab at tagging these pumps.

- PP1: chilled water common primary pump stage:1
- PP2: chilled water common primary pump stage:2
- SP1: chilled water common secondary pump vfd stage:1 
- SP2: chilled water common secondary pump vfd stage:2 

I used stage here to stay consistent with how we do cooling stages, so maybe someone has a better name. It shouldn't represent the order that they run. Maybe we just make pump be a number tag, and then put which pump it is?? This would just mean that each pump has to have a number with it

Not to get to far ahead, but does this tagging standard take into account a district chiller system? We have total of 7 simple chiller plants throughout our district chilled water system. If they are all set up as simple chiller plants and tagged properly what would be above the chiller plant to bring it to a district wide level? Just something to consider.