Welcome to this Conservation Applied Research and Development (CARD) Webinar. 1
I am Mary Sue Lobenstein, the R&D Program Administrator at the Minnesota Department of Commerce, Division of Energy Resources. Our presenter today is Russ Landry. Russ is a PE and LEED Advanced Professional who is a Senior Mechanical Engineer at CEE. In his 27 years at CEE Russ has played a variety of roles but most recently he has been involved in new construction plan review, whole building energy simulation and other technical support to design teams and to organizations charged with project oversight and verification. He has managed on a number of CARD grants including optimization of commercial space heating boilers and this one on optimizing indoor public pool facilities. 2
Before we start, I d like to go over a few webinar basics All attendees will be in listen-only mode As questions occur to you during the presentation, type them into the question box in the GoToWebinar panel and send them to us. We will address all questions at the end of the presentation. If for some reason we don t get to all questions we will answer them later and email all participants a copy of the Q&A from the webinar. This webinar is being recorded and will be available on both CEE s and the Department s websites at a later date. Finally, the slide deck for this webinar is available as a handout on your GoToWebinar panel, and you can download it at any time during the presentation. 3
This webinar is one in an ongoing series designed to summarize the results from research projects funded by Minnesota s Applied Research and Development Fund. The Applied Research and Development Fund was established in the Next Generation Energy Act of 2007. Its purpose of the fund is to help Minnesota utilities achieve their 1.5% energy savings goal by: Identifying new technologies and strategies; Improving the effectiveness of utility conservation programs; and Documenting CO2 reductions from conservation programs. A utility may reach its annual energy savings goal Directly, through its Conservation Improvement Program (CIP), or Indirectly, through energy codes, appliance standards, behavior, and other market transformation programs. 4
$2.6 million of this fund is set aside annually for the CARD program which awards research grants in a competitive Request for Proposal (RFP) process. Since the legislation was enacted, the CARD program has: Had 8 funding cycles, with 20 RFPs posted; Received over 380 proposals; and Funded 92 research projects, representing over $21 million in research dollars. As you can see by the pie chart, projects funded to date have been in all building sectors. The subject of today s webinar is the commercial sector. I ll turn it over to Russ now who will overview the common conditions and circumstances that make pool facilities ripe for energy savings, as well as discuss applicability of various operational improvements including specific recommendations for utility program activities. 5
I appreciate the introduction and the chance to share what we ve learned in our statefunded field study. We undertook this project to better understand the energy savings opportunities from improved operation of existing indoor public pool facilities, and then to help these savings be realized by providing guidance to utilities, operators, and recommissioning providers. 6
First of all, we decided that it was worthwhile to undertake a comprehensive study to look at indoor public pool facilities because of the combination of high energy intensity and the use of specialized mechanical systems. Our experience with other specialized facilities, such as ice arenas, has shown that contractors, operators, and recommissioning agents often don t have the familiarity to fully optimize the operation of specialized HVAC and other systems. Our experiences with a few pool facilities prior to this study also highlighted the unique challenges and opportunities. 7
--Next, the primary goals of the project were to evaluate the potential for operational improvements and to develop guides for operators and recommissioning providers. --Note that the focus was on finding savings that can be achieved cost-effectively in existing facilities without the large capital expense of replacing major equipment. Rather than looking at the options available for new equipment, we looked for opportunities to improve operation of the existing equipment. --Towards this end, this we developed guides for operators and recommissioning providers. The operators guide helps identify low and no cost operational improvements, and identifies when improper operation that increases energy use needs to be addressed by a contractor. The recommissioning guide helps utility program providers cost-effectively identify savings opportunities by providing information about the special opportunities in indoor public pool facilities and the challenges of evaluating the systems that often have either no or limited connection with a central building automation system, which is usually leveraged for the collection of the majority of recommissioning study data. 8
Now, here is an outline of both the primary project aspects and the remainder of this presentation. --We started with a baseline characterization to understand the market of indoor public pool facilities in Minnesota. --Then we did detailed investigations of 6 sites, including long-term monitoring, advocating for operational improvements, and verification of improvement savings. --Based on the finding of the Baseline Characterization and the Detailed Investigations, we looked at the statewide potential savings from possible program activities and measures. --I ll also note specific recommendations that we make for CIP program activities and give you a flavor of what the guides look like. 9
Our first steps in the baseline characterization were to compile summary information about the types and quantities of buildings with indoor public pools. There is no single, comprehensive state-wide database on public pools in Minnesota so we pulled together information that was available to us from a variety of sources. The list here shows the primary sources of information for each of the major building types. --First of all, for public schools we phoned a sample of school districts from throughout the state to determine the frequency of pool existence in each type of school. We then combined that information with statewide school count information from EducationBug. --While not exhaustive, the Explore Minnesota database appeared to capture data for the vast majority of hotels and motels in Minnesota. --Counts for fitness centers, and other facilities like community centers, was based on combining information from listings of sites on each chain s website, and a variety of other searches. --Finally, the statewide number of multifamily buildings with indoor public pools was estimated by extrapolating the number licensed in suburban Ramsey county using the ratio of population in this jurisdiction to the statewide population. The suburban Ramsey county database extrapolation was also a secondary source and reality check for the other facility types. Based on the summary information about facilities and pools, we then carried out on-site surveys of 30 facilities chosen to be representative of the variety of facility types and pool types. This included 15 facilities that we expected to have pools larger than 2,000 sf, and 15 facilities that we expected to have pools smaller than 2,000 sf. This small and large pool 10
grouping was based on indications that the equipment, operations practices, on-staff expertise, and corporate resources tend to be different for the small and large pool facilities. --For each facility, the on-site survey captured information about the pools themselves, the pool room, the HVAC equipment, the pool pump and heating system, the operating conditions, and also included an operator interview. 10
Our baseline characterization found that there are about 2,200 indoor public pools in Minnesota in about 2,000 facilities, and that about 900 spas are within these same buildings. --This slide shows the relative count of each category of indoor public pools, with small pools in blue, large pools in red, and spas in green. Again the split between small and large pools was chosen at 2,000 square feet. --There are about 2 and a half times as many small pools as large pools. 11
However, when it comes to total pool surface area in the state, this next graph shows that the lion s share of pool area is found in the fewer number of large pools. Surface area along with pool room area is a good indication of the energy use associated with the operation of a pool. When looked at in this way, the larger number of small pools represent only 30% of the total area of indoor public pools in Minnesota, while large pools represent two-thirds of the total area concentrated into a smaller number of facilities. This is because the average size of the large pools is more than 5 and a half times the average size of the small pools. More detail on the distinction between small and large pool sizes is shown on the next graph. 12
You can see in this frequency distribution plot that pools tend to be either much small or much larger than the 2,000 square foot area selected as the category boundary. --When the spas are excluded, the average size of the small pools is 670 square feet compared to a 3,700 square feet average for large pools. --Now that the pool size differences and their importance has been noted, it s time to look at what types of facilities house these various categories of pool categories 13
Each bar on this 3D graph represents the number of pools Minnesota within a specific pool category and facility type. The different facility types are shown across the front, left-hand axis. The pool categories are shown along the right-hand axis with large pools represented by the red bars in front, small pool counts represented by the blue bars in the middle, and the number of spas represented by the green bars in back. --Public schools, and then fitness centers contain the most large pools, respectively. Note that a fraction of these facilities also have a second pool that may be large or small, and that nearly all fitness centers also have a spa. --Note that multifamily buildings house the largest number of pools (972), but these are virtually all small pools, and a fraction of these buildings also have a spa. --Finally, the far left hand bars show that hospitality buildings house 433 small pools and a nearly equal number of spas. A very small minority of hospitality buildings have a large pool. 14
Before we dig into more detail of the on-site survey findings, a brief overview of pool conditioning requirements and mechanical systems will be useful for context. --Indoor pool facilities have energy intensive, specialized conditioning requirements. First of all, the pool water must be filtered, treated, and kept at a temperature that is comfortable for the occupants based on the type of pool activity. As shown on the bottom left, all indoor public pools have a continuously operating pump and filter system to recirculate water, as well as a heat source that adds based on a measurement of the water temperature in the recirculation piping. --The right hand side shows an HVAC unit that is used to condition the pool room space. In order for swimmers to be reasonably comfortable while not in the pool, the pool room is typically kept at a temperature near the pool water temperature. Constant evaporation of the pool water into the pool room air also elevates the humidity so some form of humidity control is provided in facilities both for reasons of comfort and to prevent water condensation on building surfaces. Since outdoor air is dryer than pool room air for the vast majority of the time in Minnesota, a number of public pools simply use outdoor air to dehumidify. Others dehumidify by recirculating the air through a compressorized dehumidifier. The air conditioning compressor(s) cool the humid air to remove moisture, then use heat reclaimed from the refrigeration system to warm the air back up. --In addition to heating and dehumidifying, the HVAC system must also continuously provide a minimum amount of fresh outdoor air while exhausting air. The fresh air and exhaust is needed to dilute and remove chloramine gases. These chloramines are a byproduct of the chlorine disinfection and contaminant neutralization process. Besides being harmful to people in high concentrations, they are highly corrosive and cause the chlorine 15
smell that is often noticed in pool areas. While this continuous supply of fresh air must often be heated, it is noteworthy that this outdoor is usually much dryer than the pool room air and provides a continuous degree of dehumidification. --In addition to proper operation of each individual piece of equipment, optimized operation of these facilities requires careful balancing between pool temperature and the combination of air temperature and humidity. Modest changes in any one of these can throw off the balance and have large energy and comfort impacts. For example, the water evaporation rate is primary factor in the pool water heating load and the dehumidification load. You can think of the evaporation like an uncovered pot on a very low boil, and changes to either of the temperature or the relative humidity can have a big impact on this evaporation rate and the associated loads. 15
Now, back to the results of baseline characterization work. One category of information we recorded from the 30 surveyed sites is basic information about the existing mechanical equipment serving the pool and pool room. --First of all, most facilities use sand filters and a constant speed pump. The sand filters have higher pressure drops than some alternatives and their pressure drop changes moderately over time. --All of the surveyed pools use natural gas as the fuel for heating the pool water. Secondary heat exchangers are used in all of the large pools and 2/3 of the pools overall. These secondary heat exchangers were commonly fed in each of three different ways: a central boiler, a dedicated boiler for the pool end-uses, or a seasonal switch between both of these. The remaining 1/3 of pools use a packaged commercial pool heater. --The HVAC systems included a compressorized dehumidifier dehumidifier more often than not. Interestingly, this appeared to be driven by facility type as much as by pool size. While 2/3 of the large pool facilities use compressors, amongst small pool buildings surveyed all of the hospitality buildings have a compressorized dehumidifier and none of the multifamily buildings do. The remaining buildings use outdoor air only for dehumidification. --The HVAC systems use boiler coils for heating in all of the large pool buildings surveyed and 1/3 of the small pool buildings. The variety of heating sources used in the other pools rooms included direct-fired make-up air unit, and dehumidifier hot-gas reheat in combination with electric resistance. --Lastly, advanced HVAC energy design features were primarily found in systems serving the large pool facilities. This included HRVs in 1/3 of these buildings and the original design of 16
dehumidifier heat reclaim for pool water heating in ½ of them. 16
Another key category of on-site survey findings is the actual operating conditions. --First of all, we found issues with HVAC control to be very common. This includes problems such as: failed sensors, building automation system communication with specialized units, a lack of operator understanding of the controls, and space temperatures that were well below the recommended values. --Another important finding is that some of the commonly heralded energy design features for pool facilities are no longer being used. Most notable in this category is pool covers that are not used, and the abandonment of heat reclaimed from a dehumidifier compressor for pool water heating. While pool covers provide savings by eliminating water evaporation while being used, many existing covers are not being used because of disrepair, the amount of effort involved, and/or concerns about water and air quality. --Our survey also found opportunities for improved pool water pumping operation to be common. In most small pool facilities, the pool water recirculation rate is much higher than the code required rate. While large pool facilities tended to have their recirculation rates more in line with code requirements, they only did so by choking down valves by a substantial amount. The picture shows an example of flow having been moderated by choking down the blue-handled valve which is fully open when it is parallel to the pipe and closed when perpendicular. These choked down valves make the pumps work harder than if the pumps were properly sized to begin with, or operated at a slower speed to get the correct flow. 17
After completing the Baseline Evaluation, we used the results of it to guide Detailed Investigations at 6 sites. 18
I m not going to step through all of the details, but am just showing this table to give you a flavor for the types of things considered in choosing the 6 sites for in-depth evaluation. There were a variety of building types with two buildings that have small pools and four buildings with large pools. Half have compressorized dehumidifiers, and 5 of the 6 have a common HVAC system configuration. Most of these also have an energy design feature that was considered as possibly providing an opportunity for improved operation of this existing equipment. --For each of these sites we reviewed plans, made on-site observations and spot measurements, carried out long term monitoring, developed recommendations for operational improvements, advocated for specific improvements, and verified the outcome of improvement efforts. 19
All of the items presented have a payback of less than three years and most have been successfully implemented at the sites and had the savings validated. The average annual savings per measure identified was 29,000 kwh and 3,700 therms. These savings average 6.5% of electrical usage and 12% of gas usage for the mechanical equipment serving the pool spaces and the pools. The most important opportunities for cost-effectively achieving energy savings in these facilities were HVAC control setting and control system changes while pool covers offer more modest opportunities. --These energy cost saving control opportunities had some noteworthy traits. The two largest saving measures, plus the 4 th largest, included outdoor ventilation air flow reduction as a primary feature. The two lowest saving no-cost control setting changes could be made without accessing a building automation system, while the top 4 saving measures require changing settings and/or programming of a building automation system (BAS) or similarly sophisticated individual HVAC unit controller. While a number of problems with existing control systems provided opportunities for improvements, these problems also included problems with communication between BAS systems and pool area HVAC units or BAS trend logging that made thorough investigation of opportunities challenging. --The one cost-effective pool cover opportunity identified in a large building was for repairing an existing cover, rather than covering the full price of purchasing and installing a cover. The pool cover opportunity noted for the hospitality building is for the use of an invisible liquid pool cover material that reduces evaporation when the water is still. The savings shown and (and less than one year payback) is based on an engineering estimate of savings, while the actual savings observed through monitoring was only a small percentage of this projected savings. While this liquid pool cover technology appeared to have the 20
potential to be the largest impact measure for a number of small pools, it s unclear now indicative the disappointing result at the one site is of the potential savings in other Minnesota indoor public pools. 20
This table provides a comprehensive look at the savings opportunities that we quantified at the sites receiving in-depth evaluations. --First of all, I d like to note that the first two rows show the difference between the expected savings from a liquid pool cover retrofit at a hospitaliy building and the observed savings. There were possibly some confounding changes at this test site that may have skewed the results. This included a possible change in the outdoor air intake rate, and a drastic change in the conditions in the pool mechanical room. --The next two rows highlight the difference in control setting changes in the summer vs the heating season. --Finally, the first two rows for SC17 showed observed energy cost savings for a regular pool cover that were in line with engineering estimates. The next row shows projected savings for using a high efficiency seasonal boiler year-round, instead of switching to the schools steam boilers during the heating season. --The difference in projected vs observed control savings in the two SC23 rows was caused by improper heating valve control logic that was inadvertently introduced when the HVAC unit was reprogrammed with reduced airflow during unoccupied overnight time periods. --The last two rows show significant savings in the two fitness center facilities. 21
The results from both the Baseline Characterization and Detailed Investigations were combined along with additional with engineering estimates to quantify the statewide savings potential associated with various measures and services. 22
Here is a summary of the state-wide savings potential in indoor public pool facilities in Minnesota. --.. 23
All of the above results were used to guide the concluding recommendations regarding CIP program efforts to capitalize on the savings potential found in indoor public pool facilities in Minnesota. 24
--Our first and most important utility program recommendation is to promote recommissioning and/or in-depth audits of indoor public pools with providers using the recommissioning guide developed by this project as a reference. The large HVAC control upgrade opportunities and site to site variations in the details of these opportunities, make it important to have a detailed evaluation performed by a skilled recommissioning provider, and for the facility to receive follow-up assistance with implementation. The recommissioning efforts can also help with identification of cost-effective opportunities for pool pump savings. --Our second recommendation is to have a simple path for the evaluation and processing of rebates for variable speed pool pumping. With this being more of an efficient flow balancing item than a case of widely varying loads, some standard utility program approaches for evaluating and processing variable speed drive installations might not fully recognize the actual savings from this measure. --Our third recommendation is to consider offering rebates for the liquid pool cover technology, but to do some level of tracking of energy savings for the first few installations. With the mixed results in limited field trials in Minnesota, it would be worthwhile to get a better basis for long-range program planning. --Lastly, we recommend promoting the use of the new Operator s guide by facility staff and contractors. This can lead to both no-cost operational changes, and low to moderate cost work to correct operational problems. 25
Last of all, I d like to demonstrate a bit of what is in the guides that we prepared for operators and recommissioning providers. 26
This shows an excerpt from the heart of the operator s guide a checklist that gives a list of 15 regular checks that an on-staff operator or contractor should conduct regularly to see if there are opportunities to reduce the energy use of the pool operations. --For each check item noted in the left hand column, this checklist notes the recommended frequency that it should be checked and gives a brief description of how this check can save energy. --Then on the far right, the Detail column directs the user to where there is much more detailed information and guidance. For those items with gray text, the detail column refers them to an industry standard source of information most notably the two pool operators guides that have long been used for certification training in Minnesota. For those checks where the text is black and the detail column has a letter and number, the reference is to another section within this guide that provides detailed, step by step directions for how to check the item, and what corrective action should be taken. --Now we ll take a look at a couple of examples of the details that are addressed within detailed check description sections. This will include details from within the Optimal Relative Humidity check and the Seasonal HVAC Operation check. 27
This item addresses both the relative humidity control setpoint and the observed relative humidity. --The dark blue lines show the typical range of expected relative humidity setpoint. The most critical time for keeping the relative humidity low is in cold winter weather to prevent condensation on windows, window and door frames and other surfaces. As the weather warms, we recommend increasing the relative humidity above these lower setpoints to minimize both the dehumidifier energy use and the pool water heating energy to make up for faster evaporation to dry air. --The dashed lines show the range of commonly observed relative humidities. Note that the observed relative humidity is often below the setpoint because of the amount of dehumidification that is provided by the continuous outdoor air ventilation especially in colder weather. On the other hand, we ve also seen that some systems are not able to keep up with the dehumifidication load in hot, humid summer weather to the graph shows the dashed lines going higher on the right hand side. 28
29
30
Thanks, Russ. Now we re going to turn to your questions that have been coming in during the presentation. EITHER, I can handle the Q&A, OR you can do it Megan. Let s talk about which way we want to do it. 31
In addition to CEE s website, the recording of this webinar as well as the final report will be available on the Department s Applied Research and Development (R&D) web page as shown here. When available, you can link to them from either the Webinar quick link or the CARD Search quick link as indicated on this slide. The R&D web page has additional resources and information related to the CARD program and to CARD research projects which you can check out. The web address is at the bottom of this slide. 32
Thanks for participating today! We appreciate your interest in the results of CARD projects. Before we leave, I want to take this opportunity to mention three upcoming CARD webinars: On November 29 Seventhwave will give a webinar on their investigation of strategies to enhance new construction programs through performance-based design and procurement On December 7 Michaels Energy will discuss their project which tested two ongoing commissioning approaches to improve the energy efficiency of outpatient medical clinics in Minnesota. On December 14 the Center for Energy and Environment will conduct a webinar on their field study to determine the increased efficiency resulting from the installation of an innovative moisture and heat transfer retrofit device on residential furnaces. Announcements about upcoming webinars and other news related to the Minnesota utility Conservation Improvement Program (CIP) can be found in the CIP Newsletter. To sign up for the Newsletter or to receive email news on a range of other energy topics, use the link on this slide to go to the email sign up page of the Department s website. In the meantime, please contact me if you want more information on how to sign up for 33
these upcoming webinars or if you have questions or feedback on the CARD program. Also let me know of any suggestions for improving these CARD webinars to make them more relevant to you. Thanks, again! 33