Hello all,

We made a short presentation on VRF meta-data model standardization in Haystack Connect last week.

We are planning to establish a basis for tagging VRF system and we are looking for other interested community members to contribute to the working group.

Topics we need help from community leaders include, ・How to express relationship between outdoor units and indoor units including branch box

・Varieties of VRF system: cooling only, heat pump, heat recovery etc.

・Heat source: air-source, water-source etc.

・Indoor unit: cassette, ceiling, wall mounted etc.

・Data points: set temperature, operation mode, fan angles etc.

・VRF data model in Haystack 4

We are currently working on the starting document. We have already received kind offers from several community leaders. Please let us know if you are interested.

We would like to have a kick off zoom meeting early June.

Please fill out your availability from the link below.

【Schedule Adjustment】

Link:

https://docs.google.com/forms/d/e/1FAIpQLSfdOIi3dQVKez8Bo-xtm18toqr0ni9e_1JzweuihGW27Eop8A/formResponse

Due date: 6/2(Wed)

If you can’t log-on to the link, please send me an email.

My email address is [email protected].

Thank you Yuya-san,

This is a great initiative and I encourage the community to contribute to this working group.

I will sign up to this working group and attend the first meetingl

I also encourage other interested members to attend!!

Looking at you Jay Herron ;) !!

Cheers, Richard

Hello Richard,

Thank you very much for your reply and comments :)

I would be happy if I could be a help to the community.

Hello all,

Thank you very much for your interests and poll.

Based on the results of the poll, we would like to have the kick-off meeting on the following schedule.

【Date and Time】

・US: June 8th(Tue) 6pm-7pm (PDT) 9pm-10pm (EDT)

・Asia: June 9th(Wed) 6:30am-7:30am (IST) 9am-10am (CST) 10am-11am (JST) 11am-noon (PT)

I am sorry if I could not accommodate for your schedule. I will, of course, share the updates here in the community.

For the detail, please refer to the following notes. I really look forward to e-meeting you next week.

【Meeting Detail】

1, Date and Time

・US: June 8th(Tue) 6pm-7pm (PDT) 9pm-10pm (EDT)

・Asia: June 9th(Wed) 6:30am-7:30am (IST) 9am-10am (CST) 10am-11am (JST) 11am-noon (PT)

2, Zoom Link (fixed)

https://us02web.zoom.us/j/87560666817?pwd=NlZBMGsyQndZaGdiOTBCV1ZvMWtXdz09

3, Agenda

1) Introduction: Objectives, Member Introductions

2) Working Group: Project Scope, Communication and Cooperation

3) Model Definition: VRF Definition, Previous discussions on Project Haystack

4) Discussions, Next Meeting

Hello everyone,

I am sending the meeting minutes for the previous meeting.

Please see from the weblink below. (Special thanks to Brian, Rui, Mike and Tak.)

https://drive.google.com/file/d/1DVYuzUKtdF7x5fZQj8QA9nW5Eeyy-Tdf/view?usp=sharing

Basically, I am going to communicate via an email for the discussion.

I set up a google mailing list for this WG ([email protected]).

(I sent an invitation. Please let me know if you have any issues.)

【Collection of links】

·GoogleDoc: 　https://drive.google.com/drive/folders/1B78wbnQsIeRSiS8LKVabIq4SyHd41oEp?usp=sharing

·Mailing List: [email protected]

·Zoom:   https://us02web.zoom.us/j/87560666817?pwd=NlZBMGsyQndZaGdiOTBCV1ZvMWtXdz09

Yuya

Dear all,

We would like to have 2nd zoom meeting.

Please fill out your availability from the link below.

【Schedule Adjustment】

Link: https://docs.google.com/forms/d/e/1FAIpQLSfdOIi3dQVKez8Bo-xtm18toqr0ni9e_1JzweuihGW27Eop8A/viewform?vc=0&c=0&w=1&flr=0

Due date: 6/22(Tue)

If you can’t log-on to the link, please send me an email.

My email address is [email protected].

I really look forward to meeting you again.

Best regards,

Yuya

Dear all,

Thank you for taking the time to answer the form. I would like to set up a meeting by below schedule.

【Meeting Detail】

1.Date and Time

・US: July 1st(Thursday) 6pm-7pm (PDT) 9pm-10pm (EDT)

・Asia: July 2nd(Friday) 6:30am-7:30am (IST) 9am-10am (CST) 11am-12am (AEST)

2.Zoom Link (fixed)

https://us02web.zoom.us/j/87560666817?pwd=NlZBMGsyQndZaGdiOTBCV1ZvMWtXdz09

3.Agenda (tentative) 1)VRF modeling on Brick Schema -Rui 2)Proposal - Annie 3)Proposal - Yuya 4)Discussions 5)Action items and next step

Thank you very much in advance.

Best regards,

Yuya Saito

I am sending the meeting notes for the 2nd meeting. Please see from the weblink below. (Special thanks to both speakers, Rui and Annie)

https://drive.google.com/drive/folders/1B78wbnQsIeRSiS8LKVabIq4SyHd41oEp

I also stored the slide received from Annie in GoogleDoc.

https://drive.google.com/drive/folders/1uBuEU9_R9CV2fN1_R0ifW7bOXbG6DR-9

Thank you for taking the time to answer the form.

I would like to set up 3rd meeting by below schedule.

【Meeting Detail】

１Date and Time

・US: August 2nd(Monday) 6pm-7pm (PDT) 9pm-10pm (EDT)

・Asia: August 3rd(Tuesday) 6:30am-7:30am (IST) 9am-10am (CST) 11am-12am (AEST)

２Zoom Link (fixed)

https://us02web.zoom.us/j/87560666817?pwd=NlZBMGsyQndZaGdiOTBCV1ZvMWtXdz09

３Agenda (tentative)

We are going to share the agenda later.

I am sending the meeting notes for the 3rd meeting. Please see from the weblink below. https://drive.google.com/drive/folders/1B78wbnQsIeRSiS8LKVabIq4SyHd41oEp

Thank you!

I would like to update the current status of the VRF system working group.

In June, we started to discuss about what kind of major components (equip) of VRF system have to be defined. Then, we are planning to move onto the taxonomy and data points for each equip.

We are currently discussing about the necessity and content of “VRF system” (equip) which integrate all the related equipment of the same VRF system such as indoor units and outdoor units.

We are also discussing about the taxonomy of VRF system components including VRF indoor unit which is likely to be separated from existing Air handling Equip in Haystack.

This WG has written the following draft proposal for the VRF system and would like to move this topic to review. Thanks to everyone who has contributed to this process so far. We look forward to hearing from the Haystack community. Please see below a summary of the proposed model and the documents with more details on the proposal.

1. General Information on VRF systems

   VRF systems have the following characteristics:

   • Refrigerant is the only material conducting heat: VRF uses refrigerant as the cooling and heating catalyst.
   • The refrigerant is conditioned by one or more condensing units and is circulated within the building to indoor units.
   • Multiple indoor units are connected to a single refrigerant circuit
   • Outdoor units can vary and control the amount of refrigerant flowing to each of the indoor units

   There are three basic types of VRF systems, cooling only, heat pump and heat recovery

   • Cooling only: Cooling only VRF systems can only cool. Heating is not available.
   • Heat pump: Heat pump VRF systems can reverse the direction of the refrigerant flow to provide heating or cooling to the indoor space. All indoor units connected to a heat pump system can use individual control and set points, but they operate in the same mode of either heating or cooling at any given time. (We propose to change the current definition of the heatPump under AHUs to a more generic one.)
   • Heat recovery: Heat recovery units are heat pump systems that can provide simultaneous heating and cooling. All indoor units connected to a heat recovery system not only can use individual control and set points, but they can also individually operate in heating or cooling mode at any given time.
2. Equipment

   VRF systems mainly consists of the following equipment.

   1. outdoorUnit – Outdoor unit has one or more compressors. As each indoor unit sends a demand to the outdoor unit, outdoor unit delivers the amount of refrigerant needed to meet the individual requirements of each indoor unit. (equip)
   2. refrigerantPlant – Multiple outdoor units can be connected, and the refrigerant plant covers all the connected outdoor units. (equip)
   3. branchSelector –Branch selectors are used for heat recovery VRF system as control devices directing the liquid refrigerant or gas refrigerant to zones requiring cooling or heating (equip)
   4. indoorUnit – Indoor units operate to satisfy a heating or cooling load in a zone based on a zone thermostat temperature set point (equip)
3. Taxonomy

   Primary equip structure is listed below.

   • Equip
     • vrfEquip
       • vrf-outdoorUnit
         • vrf-outdoorUnit-coolingOnly
         • vrf-outdoorUnit-heatPump
         • vrf-outdoorUnit-heatRecovery
       • vrf-indoorUnit
         • vrf-indoorUnit-fcu
       • branchSelector
       • vrf-refrig-plant

   However, for the detailed taxonomy, please refer to the diagram of the following document. https://docs.google.com/document/d/1m99pXOfXtyPbngDIkUdjhbLvPXRaBq_s/edit#heading=h.9x98ar50s9ag

4. Points (children)

   See https://docs.google.com/spreadsheets/d/1XO_IUil3swY4PXgR8ZBzR-7pJB_lZYhD/edit#gid=2066996511

---

For the details, please refer to the following documents.

• VRF system_general description: This document provides the general description of VRF systems. https://docs.google.com/document/d/1IXzhYukQUG1amjsVUYe3gM-qOkT-cIPP/edit
• VRF system_diagrams: This document shows diagrams of different setups of VRF systems. (for example, whether the VRF system has multiple outdoor units, whether it has branch selectors (heatRecovery system) and so on) https://docs.google.com/presentation/d/1xRa5XgLxbALUiC_WOCLT9EQxgGd642MP/edit#slide=id.g140678c8f73_1_0
• VRF system_data points: This document defines the most common points for each VRF sub equipment. https://docs.google.com/spreadsheets/d/1XO_IUil3swY4PXgR8ZBzR-7pJB_lZYhD/edit#gid=1148683770
• VRF system_definition: This document provides the definition of each equipment. https://docs.google.com/document/d/1m99pXOfXtyPbngDIkUdjhbLvPXRaBq_s/edit#

I'd like to thank this WG for their hard work and all the useful documentation breaking down the concepts.

I am in favor of all the general concept presented, my only concern would be the indoorUnit and outdoorUnit tags. In my opinion the outdoorUnit tag could be misleading in certain situations. For example I have seen multiple VRF systems with water cooled condensing units located in mechanical rooms or closets. Would a more specific tag like condensingUnit be a better option? With the indoorUnit tag, while I have not yet seen a VRF rooftop unit I could image one could exist and would be problematic in the same way. In addition the indoorUnit tag seems somewhat unnecessary if utilizing the refrigerantPlantRef tagging since this would really be no different than a ahu or fcu with a chilledWaterPlantRef.

There are already the tags dx cooling and dx heating so why not adding dxPlantRef.

Hi Leroy /Frank,

Thanks a lot for your input. We have reviewed your points and propose the following:

• The issue with using condensingUnit here is that for VRF heatpump/heat recovery systems, the outdoor unit can be both a condenser (cooling) or an evaporator (heating). Although outdoor/indoor unit is the common terminology, you do make a point on the possible confusion about using outdoor unit, hence we would like to clarify the definition of outdoorUnit and indoorUnit as follows to hopefully remove the confusion.

def: ^outdoorUnit
is: ^marker
doc: "Associated with equipment outside the conditioned space"

def: ^indoorUnit
is: ^marker
doc: "Associated with equipment inside the conditioned space"

• We would like to keep the vrfIndoorUnit as VRF systems are inherently more complex systems than a typical Chiller – AHU setups and would need their own modelling to allow for customized analytics. Further down the track as more data points might be commonly available, we might also find that the children (points) of those units are quite different hence the need to define its own entity. Note that we did define the vrf-indoorUnit-fcu having the double inheritance both from the generic vrf-indoorUnit and the fcu.
• Following the changes from Haystack 3 to 4 (chilledWaterPlantRef -> chilledWaterRef) we would actually want to use refrigerantRef to reference how the sub equips of a VRF system are connected. This was not in the docs and has been added. See the second slide here.

I see your point on condensingUnit though that is a term used throughout the industry even for heat pumps it technically is flawed. Would compressorUnit be a better alternative?

While outdoor unit is a term commonly used in VRF documentation, outside of that context it serves little meaning in my opinion. I recognize matching it with a vrf tag helps that, but the merits of the outdoorUnit tag alone provides little value especially when considering water source units which could be located anywhere, including in the conditioned space.

Hello Leroy,

I got your point. I felt creating new equip “compressorUnit” might work, but it could be confusing. We might have another question such as “Does condensingUnit come under compressorUnit?”.

I also think it is not common to have condensing water source units in the conditioned space. Keeping outdoorUnit sounds simple and understandable to me.

What do you think?

In the Haystack Labs WG, as part of our work on Attributes we have been evaluating the use of individual tags in new ways to help describe attributes of equipment. As part of this we have considered concepts like compound tags which break each camel case tag down into it's individual parts. All of this is currently just conceptual, but it makes you start looking at tags from a different perspective and thinking about the meaning/value of each component of a tag.

When I look at the definition provided:

outdoorUnit – Outdoor unit has one or more compressors. As each indoor unit sends a demand to the outdoor unit, outdoor unit delivers the amount of refrigerant needed to meet the individual requirements of each indoor unit. (equip)

It seems like the standout feature of this piece of equipment is that it has compressors, not were it is located.

In my opinion this falls in the category were terms used in the industry may not align with the best tags to use, an example of this is "Hot Water Supply", is the term most use; however leaving hot water are the tags used because they were deemed more descriptive.

As far as confusion between condensingUnit and compressorUnit, I agree they both should not exist, and given the valid points others have made I now think compressorUnit would be preferred over condensingUnit. It's definition should probably include something about it consisting of one or more compressors and a heat exchanger (condenser coil), which would differentiate it from being just a compressor.

Most of these arguments also apply to the indoorUnit tag, which I agree with Frank seem unnecessary given fcu and ahu already describe its functionality. However, if having a refrigerantRef tag is not a sufficient differentiator simply adding a vrf tag seems like it would be without the need of indoorUnit.