EBCx Workshop Series 16

Existing Building Commissioning Workshop Series 16 Materials

As indicated on the main page, the true source for the materials for the existing building commissioning class workshop is the FTP site Ryan maintains. If you need information regarding how to access it, you should contact him via e-mail at R2S2@pge.com. It would be desirable to include the words "EBCx Workshop Series Materials FTP Site Access" in the subject line to catch his attention.

The materials below are the materials I provide for the portions of the workshop that I teach. I am going to keep placing them here so that you can access them before class if you want and also to make it easy for Ryan to pull them back for the FTP site.

Note that most of the time, I include a "READ ME" file in the zip file with the materials and resources that describes what each of the files is about.

Session 1

The files below are the files I will be using in class today. Note that I uploaded a revised version of the scoping slides around 10:00 AM that includes the slide with the ASHRAE link in it.

LECTURE

scoping_and_findings_list_v4.pptx
File Size:	59077 kb
File Type:	pptx

SCAVENGER HUNT

scavenger_hunt_v1_ho.pptx
File Size:	9990 kb
File Type:	pptx

cw_system_v11_suv8_ncv.zip
File Size:	2815 kb
File Type:	zip

cooling_towers_v9_suv8.zip
File Size:	8965 kb
File Type:	zip

mechanical_space_v2_suv8.zip
File Size:	19118 kb
File Type:	zip

le_conte_annex_ahu_suv8_v11_ncg.zip
File Size:	100852 kb
File Type:	zip

FOLLOW UP

scavenger_hunt_-_answers_v1.pptx
File Size:	12960 kb
File Type:	pptx

The file to the left is the "answer slides" for the cut away chiller along with the other compressor pictures that I shared.

There were also a number of people who wondered if the electronic psych chart I demonstrated worked on a MAC and/or if the ASHRAE chart would work on a MAC. The answer to that is "No".

But there some other options that you may want to consider. One is that ASHRAE does publish an iPad psych chart app. If you go look at it on the App Store, it does not have a lot of stars, but the reviews say that is because it is buggy. I bought a copy to see how well it worked (its $20, so not to terribly expensive) and so for, for me, it has worked nicely. The screen shot below is from it.

Another option is an app called HVAC toolkit. It is from the same company as the one that developed the ASHRAE Psych Chart app. You can buy different modules including a psychrometrics module. It doesn't plot on a chart but it does give you all of the parameters associated with any point that you enter in terms of a dry bulb temperature and one other metric, for instance relative humidity, as illustrated to the left.

If you follow the link, you will find that there are quite a few options in terms of the features you get with a given module or collection of modules. For instance, you can get a basic psychrometric calculator like I describe above for about $1.00. I have had the HVAC toolkit package for years now and it has been well worth the $20 or so I spent on it a while back.

I also mentioned that I would be putting together an answer video for the scavenger hunt that we did in class. That is still on the radar but probably will not be done until mid to late August, so check back ever once-in-a-while if you are interested in that.

Finally, Ryan should be sending out an e-mail with instructions for the exercise we gave you using the Le Conte AHU model. So watch for that in your inbox.

Session 2

The files below are the files I will be using in class today.

LECTURE

01_-_introduction_to_system_diagrams_v2.pptx
File Size:	14033 kb
File Type:	pptx

plant_v41_suv8.zip
File Size:	111155 kb
File Type:	zip

02_-_variable_flow_plant_discussion_v5.pptx
File Size:	2112 kb
File Type:	pptx

cooling_towers_v11_suv8.zip
File Size:	20773 kb
File Type:	zip

LAB

system_diagram_lab_handout_v1.pptx
File Size:	3070 kb
File Type:	pptx

control_system_history_v2.pdf
File Size:	126 kb
File Type:	pdf

shedule_and_points.pdf
File Size:	9308 kb
File Type:	pdf

Session 3

The files below are the files I will be using in class today.

LECTURE

lecture.zip
File Size:	33264 kb
File Type:	zip

LAB

lab.zip
File Size:	9400 kb
File Type:	zip

light_switch_v2.pptx
File Size:	268 kb
File Type:	pptx

FOLLOW UP

The file to the right is the working copy of the logic diagram tool that I used in class, meaning it has the answer we developed together in it.

logic_diagram_tool_-_class_example.xlsm
File Size:	1656 kb
File Type:	xlsm

There were also a number of other resources that were mentioned in the class in addition to the links in the slides that Ryan, Sweta and I used.

Hourly Weather Data

With regard to hourly weather data, I have found the Iowa State ASOS site to be a very fast way go get hourly climate data for a large number of locations.

http://mesonet.agron.iastate.edu/request/download.phtml?network=OR_ASOS

The primary benefit in my perspective is that the time and date stamp used in the dataset is already compatible with Excel, and you can select a time zone. This saves a number of processing steps compared to retrieving data from NOAA, which uses the UTC time stamp and a time and date stamp that needs to be converted to a value Excel can read. You will find information on both resources in this blog post. And the NOAA site is worth knowing about because it has a larger inventory and probably can go further back in time than the Iowa State site.

This blog post will provide guidance and examples of how to work with the time and date stamp used by the NOAA data (at least the last time I used it) and convert it into an Excel compatible format. It also provides some general insight into how Excel works with dates an time.

This blog post is the original post I did about the NOAA resource. It also provides information about how to open a delimited file in Excel, which may be helpful because files from data loggers and control systems are often exported in some sort of delimited format.

Also, note that there is a "Weather and Climate Resources" category available from the drop down menu on the right side of the blog. If you select it, the page will fill with links to all of the posts that have information about weather and climate data, including the ones I have highlighted here.

Economizer Stratification

Ryan mentioned how important it is to use multiple sensors in a mixed air plenum because of the potential for temperature and velocity stratification, which can be quite extreme and also dynamic, varying with the position of the dampers as well as the flow rate occurring at the time. The Economizer Stratification page of this site illustrates this in a number of ways and also contains a link to a blog post that looks at the issue in a system we played with in a previous EBCx class. You will also find information on the topic in the materials from the Economizers, Design, Performance and Commissioning Issues class that we occasionally provide at the PEC.

Point List Resources

Monitoring plans are a form of the point lists that are used to define a control system design. So, point list resources may be helpful to you as you work on your monitoring plan. Ryan mentioned using some sort of naming convention as you develop your list and the tool I shared with you and discussed briefly might be helpful.

We also mentioned a number of other resources and I have updated the Monitoring Plan Spreadsheet page to include them. Note also that there is a little 20 or so minute video module included on the page where I walk you through some monitoring plan concepts and illustrate what you might want to be thinking about as you develop your monitoring plan.

Session 4 (Thursday Class)

The files below are the files I will be using in class today.

CONTROL LOGIC LAB - WORKING WITH PHYSICAL LOGIC AND A COOLING TOWER

cooling_towers_v9_suv8.skp
File Size:	33524 kb
File Type:	skp

2020-11-12_cooling_towers_and_control_logic__v1.pptx
File Size:	4810 kb
File Type:	pptx

mechanical_space_v2_suv8.skp
File Size:	43858 kb
File Type:	skp

A FIELD INTRODUCTION TO REFRIGERATION SYSTEMS AND HOT GAS BYPASS

hot_gas_and_vapor_compression_v1.pptx
File Size:	15770 kb
File Type:	pptx

exploring_a_chiller_v1.pptx
File Size:	13108 kb
File Type:	pptx

Here are a few resources that will help you learn more about refrigeration processes and systems.

This Sporlan application guide is a really well written, approachable guide about how to use a pressure-enthalpy chart to assess a refrigeration cycle.
Copeland offers their refrigeration engineering application guidelines at no cost at this location.
Roy Dossat's book Principles of Refrigeration is a very well written, easy to understand, written in layman's terms book that comprehensively covers the topic. The link takes you to a blog post that will give you more insight into that. At one point, a .pdf of the first edition was available from an archiving site, but that seems to no longer be there. So, you would have to purchase a copy if you wanted one. But there seem to be used copies available in the $20-$40 price range from several on-line book sellers.
Variable flow refrigeration systems are becoming more common. At one point, I compiled a bunch of information I had gathered on the topic and shared it on the VRF Systems page of the web site.

Sporlan in general has really great engineering and application guidelines available on their website in the support area. To save you some time, the zip file to the right contains the ones that are the most relevant in the context of our discussion today.

sporlan.zip
File Size:	15972 kb
File Type:	zip

Session 5 (Friday Class)

The files below are the files I will be using in class today. Note that I modified the hot bas bypass slides from what I put up yesterday. Please delete what you downloaded yesterday and replace it with the slides below.

A FIELD INTRODUCTION TO REFRIGERATION SYSTEMS AND HOT GAS BYPASs (Revised)

hot_gas_and_vapor_compression_v2.pptx
File Size:	29974 kb
File Type:	pptx

I will reference this video in class; it shows what bubbles look like in a refrigerant sight glass (a.k.a. a cloudy sight glass)

PICTURES FROM THE FIELD

field_trip_findings__no_video_v4.pptx
File Size:	91028 kb
File Type:	pptx

wusm_w_bldg_cond_pump_20091008to20091012.csv
File Size:	1302 kb
File Type:	csv

energy_star_thermal_conversions.pdf
File Size:	317 kb
File Type:	pdf

steam_and_condensate_-_no_video__v2.pptx
File Size:	16149 kb
File Type:	pptx

charts_and_table_v2.xlsx
File Size:	3813 kb
File Type:	xlsx

san-francisco-tariff-thru-al-38-updated.pdf
File Size:	16913 kb
File Type:	pdf

national_refrigerants_reference_guide_2006.pdf
File Size:	6101 kb
File Type:	pdf

FOLLOW UP

As you probably observed, we did not get to some of the materials that I handed out above in the most recent class, mostly the materials associated with steam and condensate return systems. I believe Ryan plans to reschedule them into a subsequent class so we can do the exercises we planned. But you can get a general feel for the content by reading through a string of three blog posts on the topic of the energy content of a pound of steam.

Ryan has been asked by several people for a recap of the logic assignment You will find it in the closing slide of the 2020-11-12 Cooling Towers and Control Logic v1.pptx file I handed out for Thursday. But to recap it here the assignment is to figure out how the level control system works, which will require that you come up with a wiring diagram. One way to do that is to trace the wiring out, but there are actually other ways if you are extra observant in your virtual field work in the model.

The "method to the madness" is to expose you to untangling physical logic in the field, which I have come to realize was really helpful to me in terms of understanding how control systems worked and learning how to design and troubleshoot them and develop my own control logic. Once you have untangled the wiring and made yourself a wiring diagram, I asked you to consider and answer the following questions.

What are the functions of the different terminal types in the control panel?
How much does the Warrick control relay cost?
Why did Ellis seal the electrode fitting conduit entry with caulk? (Ellis is Ellis Montgomery, one of the best control electricians I have had the privilege of knowing and being mentored by. When I build the model, I imagined him as doing the wiring and there is a little tribute to him in the model that you might come across if you are vigilant.)
How would you figure out the maximum fuse rating you could safely install in the fuse holders?
How would you figure out the minimum water level in the tower (the level that would open the make-up valve)?
What sets the level at which you would close the make-up valve?
What sets the maximum water level in the tower (the level that would cause water to run out the overflow)?

The purpose of these questions is to help you think about the sort of abstract nature of the logic in the context of the physical reality it is associated with. There are practical reasons for some of the hardware, cost is a consideration, code requirements will come into play if you set out to do something like this, and the set points you would select have a physical reason behind them.

Several people wondered if I had an example of logging a hot gas bypass and I do. I added those slides to the steam_and_condensate_-_no_video__v1.pptx file thinking I would share them at that point. But since we did not get to that point, I have uploaded the revised slides above as steam_and_condensate_-_no_video__v2.ppt. I am working on a narrative that looks at the trend data that we pulled from the installation that is depicted, which, when combined with other data, allowed us to demonstrate that the hot gas bypass system was not very well tuned and will upload that once I finish it (or turn it into a blog post; either way, I will post something here so check back).

We also discussed temperature and humidity control for a facility that housed musical instruments. Several years ago, on one of our field trips to UC Santa Cruz, we ran into something like that and I did some analysis and discussion with the class. The results were summarized in one of my annoyingly long e-mails. For those who are interested, I have included that below along with the supporting information in a zip file. Let me know if you have questions.

2014-01-26_follow-up_memo.pdf
File Size:	6887 kb
File Type:	pdf

music_center.zip
File Size:	981 kb
File Type:	zip

We talked about how refrigeration systems leverage saturated system physics in class. The national_refrigerants_reference_guide_2006.pdf file above contains refrigerant tables for many common refrigerants and if you study them, you will see how at saturation (the condition that exists in a condenser and evaporator), there is a very specific pressure associated with the temperature that the process is occurring at and that this varies from refrigerant to refrigerant for a given temperature condition. You may also find the thermodynamic diagrams for R-134 that I included on the Thermodynamic Diagrams Spreadsheet page to be of interest since they provide a "visual" on this for R-134.

Session 6

The files below are the files I will be using in class today.

CONTROL LOGIC LAB - COOLING TOWER EXERCISE ANSWER, HEAT EXCHANGER LOGIC EXERCISE INTRODUCTION

All of the materials you will need for this exercise are on the Bureaucratic Affairs Building HHW System Logic Exercise page. We will also be offering two, optional one hour support sessions for this exercise. Ryan will be sharing the meeting invites with you, but I also think (but am not sure) the following links will work.

You are welcome to attend none of them or any and all of them. If the space cadet giving them can remember, they will be recorded and posted on this website for future reference.
As of the time I am posting this, the cooling tower exercise answer key is still a work in progress. We will spend the first 10-15 minutes of the lab rotation discussing the answers in general. We will also use the PowerPoint file below to discuss how the Warrick Level Control System works. I will ultimately include a detailed answer key in the follow up information after class.
Having said that, Bob VanBlargan (one of your colleagues) was first to respond with some answers to Ryan and I and graciously agreed to present them as a starting point for discussion with yours's truly providing color commentary. The file he plans to share is linked below.

presentation_vanblargan.docx
File Size:	20 kb
File Type:	docx

warrick_circuit_v3.pptx
File Size:	217 kb
File Type:	pptx

INTRODUCTION TO FUNCTIONAL TESTING

The file below is the file I plan to present in class. Given the time we have, I can't go into quite as much depth as I would like to. But, thanks to a number of clients, I was able to take the time to record a more detailed version of the slides I will present tomorrow. You will find those videos posted on the Introduction to Functional Testing on demand training page of the website. The first two modules provide a bit more depth on the topics I will try to cover in class tomorrow.
The last two modules are a case study that illustrate how we developed a functional test to ask a building about the possibility of implementing a thermal flywheel cycle to solve an operational problem. It turned out that we could and implementing the cycle also delivered an energy savings benefit.

introduction_to_functional_testing_v8.pptx
File Size:	9611 kb
File Type:	pptx

PERFORMING A PUMP TEST

The files below will be used for the pump test portion of the class. We will also be using the video on the Testing a Pump page. The Pump Test Demo file is the test we would do if we could meet in person at the PEC and is similar to the example I use in the case study in the PowerPoint. It is the lab assistant version, meaning it has the answers included along with the key "take-aways" documented. It also includes a system diagram and a pump curve.
In class you will do an exercise to develop the test associated with the case study. I will provide a copy of that test in the follow-up materials, but I didn't want to give the answers away ahead of time by posting it now.

testing_the_pec_ice_storage_system_v2.pptx
File Size:	9228 kb
File Type:	pptx

pump_test_demo_-_lab_assistant_version_v2.pdf
File Size:	1472 kb
File Type:	pdf

Session 7

The files below are the files I will be using in class today.

CONDENSATE PUMPS

steam_and_condensate_-_no_video__v2.pptx
File Size:	21636 kb
File Type:	pptx

charts_and_table_v2.xlsx
File Size:	3746 kb
File Type:	xlsx

wusm_w_bldg_cond_pump_20091008to20091012.csv
File Size:	1302 kb
File Type:	csv

san-francisco-tariff-thru-al-38-updated.pdf
File Size:	16913 kb
File Type:	pdf

energy_star_thermal_conversions.pdf
File Size:	317 kb
File Type:	pdf

In addition to the files above, the following strings of blog posts discuss the topic we will be looking at in more detail and provide additional examples of the concepts we will discuss.

The string of three blog posts starting with What is the Energy Content of a Pound of Condensed Steam? (Part 1).
The string of five blog posts starting with Assessing Steam Consumption with an Alarm Clock.

AIR HANDLING UNIT LAB

The files below will be used for the lab session in the afternoon.

ballroom_ahu_v23_suv8.zip
File Size:	19078 kb
File Type:	zip

ahu_lab.zip
File Size:	7863 kb
File Type:	zip

The video below is an animated fly-through of the ball room AHU model that includes a table of contents and you may find it helpful as a way to find a location or scene that you want to view in the model.

FOLLOW UP INFORMATION

During class, we discussed expansion tanks and I mentioned a resource from the Bell and Gossett website that I thought was a good reference on the subject as well as on air control in general in hydronic systems. You will find that resource at this link along with a number of other really good references. The specific resource I was thinking of is Air Management Sizing And Installation Instructions For Hydronic Heating/Cooling Systems.

We also had a discussion about variable speed drives and I mentioned that there was an issue that I should mention but we never got back to it. The slide to the right summarizes it, in particular, the line that says Hub bolts and shafts have to deal with this when starting against a reverse spinning motor.
If they don't "deal with it", they shear, which sets up a really dangerous situation. For an example of that, read the side bar titled "Shear Luck" in the file below, which is from the Functional Testing Guide.

tg07-power_failure_recovery.doc
File Size:	2117 kb
File Type:	doc

There are also a number of other things to be aware of regarding moment of inertia and how motors interact with centrifugal loads in general. The 5th (final) video on the on demand training Induction Motor Principles page goes into this if you are interested. The other videos on the page go into the basics of how induction motors work and their performance characteristics.
Appendix 6 of the NBCIP Return Fan Capacity Control Guideline also has some useful information in it regarding variable speed drive and motor considerations.

During class, I shared the more detailed version of the Hijend Hotel chilled water system diagram to illustrate how you could handle a large system diagram that spans multiple sheets. I have shared that file to the right in case it is helpful for you as you develop your system diagrams

chw_system_diagram_v7.pptx
File Size:	3461 kb
File Type:	pptx

The topic of die penetrant inspection came up at one point. I dug back into some of my old Airplane Mechanic references and scanned the section from Advisory Circular AC 43-13, which is the official reference you would use for inspection and repair techniques for aircraft if there was no manufacturer specific instructions for a given need. The link takes you to the full document if you are interested. While focused in aircraft, a lot of the information is generally applicable.

ac_43-13_die_penetrant_inspection.pdf
File Size:	2370 kb
File Type:	pdf

Finally, I also sent out an e-mail with a OneDrive link to some downloads on valves and archival storage. The content is something I probably should not post on a public domain site, which is why I handled it that way. If you didn't get the e-mail, let me know and I will send it again.

Session 8

LAB AND LECTURE

The files below are the files I will be using in class today. I tried something new this time to help you locate materials as we go through the session by linking to them from the slides. But that means you will need to unzip the files into the same file structure that I have them in on my machine. If I did all of this correctly, that should automatically happen. But once you unzip the files, you need to not move them unless you move them collectively so that the relative links are preserved.

2021-02-11.zip
File Size:	111617 kb
File Type:	zip

FOLLOW UP

The discussion of preheat processes came up in class and we decided to table it for now and do a separate session on it at some point in the future. However, if you just can't wait, you will find a fairly detailed discussion of the topic in the Functional Testing Guide in the chapter on preheat. You will also find slides on the topic in the Coils Module associated with the Fans and Ducts; Design, Performance, and Commissioning Issues class.

We also mentioned the NBCIP Return Fan Capacity Control guide as a resource for understanding how to maintain minimum air flow rates in variable volume systems. The guide looks at the 5 most common strategies in detail. You will find it at the top of the NBCIP Reports page of the website.

The Flow Tracking chapter of the NBICP Return Fan Capacity Control guide includes a discussion of pitot tube traverses and contrasts the equal area method with the Log-Tchebycheff method. You will also find several other resources regarding these two methods as well as Testing, Adjusting, and Balancing techniques on the TAB Resources page of the web site.

Finally, several of you were interested in the Greenheck coil model I mentioned that illustrated how a reheat coil selected to heat using 170°F water could also do reheat using water at 110°F or less. The file below contains the model runs. To use it, you will need to install the no-cost Greenheck Coil Selection program.

logic_diagram_exercise.ghcoil
File Size:	47 kb
File Type:	ghcoil

Session 9

LOGIC EXERCISE AND LAB

The files below are the files I will be using in class today.

hw_logic_exercise.zip
File Size:	6283 kb
File Type:	zip

reset_savings_lab_-_part_1.zip
File Size:	12520 kb
File Type:	zip

April 15, 2021 Session

RESET CALCULATION LAB

The files below are the files I will be using in class today. Note that the two SketchUp models are the same other than the one with SUv8 in the name is back-saved to the SketchUp Version 8 file format in case you are using an older version of the software or viewer.

bureacracy_building_v12_reset.zip
File Size:	30921 kb
File Type:	zip

finned_tube_radiation_performance_-_basicv3.xlsx
File Size:	659 kb
File Type:	xlsx

bureacracy_building_v12_reset_suv8.zip
File Size:	26951 kb
File Type:	zip

lab_materials.zip
File Size:	1582 kb
File Type:	zip

May 6, 2021 Session

PUMP OPTIMIZATION LAB

The files below are the files I will be using in class today. Note that the two SketchUp models are the same other than the one with SUv8 in the name is back-saved to the SketchUp Version 8 file format in case you are using an older version of the software or viewer.

plant_v41.zip
File Size:	129714 kb
File Type:	zip

2020-03-02_pump_optimization_v6.pptx
File Size:	16512 kb
File Type:	pptx

plant_v41_suv8.zip
File Size:	117782 kb
File Type:	zip

01_-_optimization_exercise_materials.zip
File Size:	27492 kb
File Type:	zip

DIRECT EXPANSION (DX) REFRIGERATION

Ryan and I suspect we will not get to this today, but just in case, here is a potpourri of information I will use to discuss the topic and support a break-out session. You will find a pressure-entropy diagram for R-134 on the Thermodynamic Diagrams Spreadsheet page of the website.

vapor_compression_v10.pptx
File Size:	42886 kb
File Type:	pptx

copeland_refrigeration_manual.zip
File Size:	10504 kb
File Type:	zip

sporlan.zip
File Size:	15972 kb
File Type:	zip

evans_hall_exercise.zip
File Size:	16916 kb
File Type:	zip

national_refrigerants_reference_guide.zip
File Size:	2239 kb
File Type:	zip

copeland_screw_compressor_manual.pdf
File Size:	1122 kb
File Type:	pdf

double_suction_riser_v1.skp
File Size:	597 kb
File Type:	skp

roy_dossat_principles_of_refrigeration.zip
File Size:	32686 kb
File Type:	zip

reciprocating_compressor_manuals.zip
File Size:	7916 kb
File Type:	zip

FOLLOWUP

The file to the right is the calculation we did in class together to project the energy that was being wasted by having the pump in "Hand" instead of "Auto". You will use the same procedure to assess the various optimization options for the pump. The only things that will change will be the head and the various efficiency factors for the power calculation, depending on which option you are looking at (impeller trim, VFD, etc.)

For the energy calculation , the hours and the cost of electricity will vary with the location you are considering.

class_example.xlsx
File Size:	49 kb
File Type:	xlsx

The file to the left is a more detailed version of the calculation we did that contrasts the savings in various locations. It also contains the digitized version of the pump curve, which you may find useful for your assessment. The "System Curves - Projected" tab illustrates the technique I showed you to project the wide open pump curve based on the design operating condition and the pressure drop you believe exists in the throttled triple duty valve. I have also included a copy of the triple duty valve curves. The valve is an 8 inch valve and you can see the model number by picking a scene in the model that has the insulation removed from the pump specialties and looking for it on the flange of the valve.

hoa_switch_assessment_r1.xlsx
File Size:	3261 kb
File Type:	xlsx

2015-03-29_tdv_curves.pdf
File Size:	4624 kb
File Type:	pdf

The triple duty valve curves have logarithmic axis scaling. This is quite common in HVAC and if you are not accustomed to it, you may want to look at the portion of this blog post where I discuss it. The file to the right is a little "cheat sheet" that I made myself to help me read log scales.

log_scales.pdf
File Size:	32 kb
File Type:	pdf

Robert discussed a domestic hot water system he was involved with and I mentioned the need to be cautious regarding temperature settings and scheduling the recirculation pumps due to legionella. The files to the left are to resources that will provide additional insight in that regard. I also mentioned that there was a case study in the Engineering Design Resources Design Brief that looked at a domestic hot water system were the storage tank pump and recirculation pump interreacted in an adverse way. You will find that brief on the Energy Design Resources page of the website; its the file named pumpsystemtroubleshooting_final-073108.pdf and the case study starts on page 9.

dhw_info.zip
File Size:	11514 kb
File Type:	zip

June 25, 2021 Session

LECTURE

We are planning to cover the direct expansion refrigeration topic today, so you will want to have the materials that were provided last session on that topic available to work with.

SCOPE OF WORK LAB

The files below are the files I will be using for the lab today. Note that the two SketchUp models are the same other than the one with SUv8 in the name is back-saved to the SketchUp Version 8 file format in case you are using an older version of the software or viewer.

plant_v41_-_back-up_pump.skp
File Size:	241654 kb
File Type:	skp

scopes_of_work_v4.pptx
File Size:	1764 kb
File Type:	pptx

plant_v41_-_back-up_pump_suv8.skp
File Size:	221882 kb
File Type:	skp

02_-_scope_of_work_-_example_r1.zip
File Size:	5390 kb
File Type:	zip

FOLLOW UP

The spreadsheet file to the right is the spreadsheet with all of the calculations behind the "answers" to the pump optimization exercise. The .pdf file is the contractor with the high bid for replacing the pump explaining why they are high.

Again, I (and Ryan also) really appreciate the effort the teams put into doing this, I know it was a lot.

1510_6g_1150_rpm_evaporator_pump_assessment_v9.xlsx
File Size:	6893 kb
File Type:	xlsx

2021-06-16_contractor_explanation_of_pump_replacement_high_bid.pdf
File Size:	539 kb
File Type:	pdf

At one point in the class, we were discussing dual path systems and the subject of a Texas multizone came up, which is a multizone with three "decks"; hot, cold, and neutral air.

pec_three_deck_multizone_v1.pptx
File Size:	4726 kb
File Type:	pptx

Neutral air is air that at or near the space condition and for a three deck multizone, it is served by mixed air. Thus, on minimum outdoor air, the deck is served by are that is near the return air condition and thus "neutral" air. The PowerPoint to the right illustrates this type of unit.

One of the issues Ali mentioned was the issue with non-uniform distribution of water over a cooling tower he was working on. This article explores the physics behind the problem he was having. This video also illustrates the dynamic. Note the piping configuration serving the cold basins shown in the still at about 7 seconds into the video.

The supply first reaches a tee where the branch of the tee serves one cold basin and the run of the tee continues through an elbow to the second cold basin. At low flow rates, it was easier for the water to go straight through the tee an through the elbow and the basin it served would run a bit higher than the one served by the branch of the tee.

But as the flow increased, the pressure drop through the elbow and the straight run of pipe increased (as the square of the flow, so non-linearly) and the flow started to shift to where more flow went through the branch of the tee to the other basin and the level there became higher than the basin served through the elbow. Then, as the flow continued to increase, the path of lesser resistance again became the run of the tee and pipe through the elbow and the basin served through the elbow recieved more water.

Very dynamic.

Also note that the weir arrangement for this tower is different from the BAC tower that Jeff shared in his video.

Also, in Ali's presentation I mentioned the issues that can occur if you start a VFD against a reverse spinning fan wheel. Appendix 6 of the NBCIP Return Fan Capacity Guide covers this topic and other drive system issues.

With regard to the thermostatic valves, I realized that I made a little training video for the site where I had recently encountered them, so I think between that (embedded below) and the files to the right, you will get a pretty good sense of how they work. This is covered in the first 7-8 minutes of the video.

thermostatic_valves.zip
File Size:	11237 kb
File Type:	zip

The rest of the video explains how the variable flow primary/secondary system associated with the valves works. So, if you are still working to understand that system type, you may find that part of the video to be helpful too.

With regard to the flow control valves on the coils at Gordon's facility, I believe the files in the zip file to the left will give you some insight into them. There is one valve that goes on the supply side of the coil and the "thingy" sticking down at an angle is in fact, a strainer and is oriented just as you would expect a strainer to be oriented.

griswold.zip
File Size:	4582 kb
File Type:	zip

There is another valve that goes on the return side, which also has a "thingy" sticking down at an angle, which kind of looks like a strainer. But when you install it, it will look like a strainer installed the wrong way. It is actually a flow limiting valve and the shape has to do with what it takes to get the flow to go through the cartridge that limits flow in the right direction. It basically is a little tiny version of the flow limiting valve Tony showed in class today (the one that was put in backwards).

Anyway, if there are questions on any of this, just let Ryan and I know and we will add them to the list for a class discussion.

June 25, 2021 Session

LECTURE

I made some improvements and additions to the slide set I will use to discuss refrigeration systems. So you should replace the slides set I provided previously with the slide set to the right. And just a reminder that there were a number of resources provided on this topic in the materials posted for the May 6th session.

vapor_compression_v11.pptx
File Size:	70781 kb
File Type:	pptx

LAB

The following materials will be used for the lab session.

scope_of_work_documents.zip
File Size:	477 kb
File Type:	zip

assignment_v4.pptx
File Size:	1539 kb
File Type:	pptx

load_and_flow_profile_exercise_materials.zip
File Size:	782 kb
File Type:	zip