ASHRAE Journal - September 2009 - 45

missioning recommendations, and summer 2008 and winter 2008 – 09 performance history. System Design The first task for the design effort was to define and reduce the load. Several different low-flow showerheads were tested by installing a sample at the existing facility to determine that the showerheads would suffice for the teenage girls. The administrator also assisted designers by providing some timed shower data from the current occupants to accurately predict hot-water usage on a daily basis. Based on administrator feedback, the predicted hot-water usage for the facility was estimated to be an average of 75 gallons/ day (284 L/day) on weekdays and 10 gallons/day (38 L/day) on weekends. The facility houses 12 teenage girls and their young children. Now that the facility has been operating with the solar system for the past 10 months, the actual hot-water usage has been measured and equates to 65 gallons/day (246 L/day) per person on weekdays and 5 gallons/day (19 L/day) per person on weekends. After the number, duration and time period for daily showers and laundry had been defined, the optimum storage volume was calculated. Using solar heating computer simulation software, the optimum solar panel size for this facility was determined to be a four-panel array of 4 ft by 8 ft (1.2 m by 2.4 m) panels (Photo 1). This system’s size was predicted to provide 63% of the annual hot water for the facility. We decided to use photovoltaic (PV) powered dc pumping, a new trend in solar hot-water heating systems, rather than a conventional ac powered pump. This eliminated any parasitic cost of utility power because the pumping energy would be provided by the sun. The additional benefit is avoiding a glycol loss from system boil-overs during power outages. Monitoring and Control firm donated the design work and a local chapter member’s firm donated the installation and successfully persuaded other firms to donate storage tanks and other accessories. Only the solar collectors and mounting hardware were purchased, using money donated by ASHRAE members and other Region IX chapters. Excess contributions were given to the Louisville chapter to seed its sustainability project for the 2009 ASHRAE Annual Conference. The revised chapter plan required the system to be installed and running for the ribbon cutting on June 20, 2008, the day before the Annual Conference opened. ASHRAE president Kent Peterson attended, along with other dignitaries, local government officials, and representatives of the media. Because the system and installation were donated, there wasn’t a general contractor to enforce project schedules. The project was producing hot water, along with the live Web demo, barely in time for the dedication. We would advise other chapters to allow the full year to accomplish their sustainability projects to avoid last-minute completion headaches. Getting the System to Work An automation company donated a full-featured system that could be used for system monitoring, energy performance calculations, and differential temperature control. Flow meters, temperature sensors, and other data points into the system were monitored, and Web pages of live data were displayed at the 2008 ASHRAE Annual Meeting (Figure 1). Custom automation programming was provided by Utah chapter members and firms owned by local members installed the solar piping and controls. Small solar hot-water systems typically lack the control sophistication of this project, but our automation has been essential to identifying problem areas during system commissioning. The secure project site required remote monitoring where we studied system performance data logs and fine-tuned the control software to obtain maximum energy collection (Figure 2). Installation The Teen Home was a good fit for this project because of its daily domestic hot-water usage requirements. We decided to install two 80 gallon (303 L) preheat tanks with built-in glycol heat exchangers feeding into two existing commercial 80 gallon (303 L) gas domestic water heaters. A local engineering September 2009 The design engineering firm and mechanical contractor were well respected for their conventional HVAC expertise, but they didn’t have a lot of recent solar hot-water system experience. As a result, we learned as we went. The first major issue we discovered during installation was that the company donating the storage tanks had mistakenly shipped the Florida version, which heated city water directly in the collectors without the glycol heat exchangers required by the much colder Utah climate. Since the tanks were already piped, we decided to leave them in place for the summer and correct the problem before winter. We evaluated keeping the tanks by adding a separate heat exchanger for the glycol with a domestic water pump. This would have required re-piping, modifying the controls with extra sensors, and more pump control. Fortunately, the company that donated the tanks volunteered to ship the correct tanks, and the installing contractor agreed to re-pipe them when they arrived, leaving the system operating according to its original design (Figure 3). The correct tanks were installed several months later and the glycol loop was isolated, but additional taps into the system were required to inject the glycol. In addition, once the glycol expansion tank was returned to its isolated loop function, we also had to add an additional expansion tank to handle the extra domestic hot-water storage capacity. We discovered the second major issue during the meeting while we were remotely monitoring the system. Because the home used very little hot water during the weekend, the storage tanks were reaching almost 180°F (82°C). We found the existing tempering valve was not piped correctly to inject cold water, because the original system piping schematic did not reflect the extra bypasses that we found after carefully tracing all the old and new piping. In addition, a check valve shown for the existing DHW recirculating pump was missing, so we were back-feeding very hot, solar-heated water into the system, bypassing the existing ASHRAE Journal 45

ASHRAE Journal - September 2009

Table of Contents for the Digital Edition of ASHRAE Journal - September 2009

ASHRAE Journal - September 2009
Contents
Commentary
Industry News
Letters
Meetings and Shows
Getting to Net Zero
Feature Articles
How High Can You Go? Building Height and Net Zero
Lab for Learning
Solar Hot-Water Heating System: Lessons Learned
50th Anniversary—Low Pressure Steam Heating Systems
Building Sciences
Products
Emerging Technologies
People
Classified Advertising
Advertisers Index
ASHRAE Journal - September 2009 - ASHRAE Journal - September 2009
ASHRAE Journal - September 2009 - Cover2
ASHRAE Journal - September 2009 - 1
ASHRAE Journal - September 2009 - 2
ASHRAE Journal - September 2009 - Contents
ASHRAE Journal - September 2009 - 4
ASHRAE Journal - September 2009 - Commentary
ASHRAE Journal - September 2009 - Industry News
ASHRAE Journal - September 2009 - 7
ASHRAE Journal - September 2009 - 8
ASHRAE Journal - September 2009 - 9
ASHRAE Journal - September 2009 - Letters
ASHRAE Journal - September 2009 - 11
ASHRAE Journal - September 2009 - 12
ASHRAE Journal - September 2009 - 13
ASHRAE Journal - September 2009 - 14
ASHRAE Journal - September 2009 - 15
ASHRAE Journal - September 2009 - Meetings and Shows
ASHRAE Journal - September 2009 - 17
ASHRAE Journal - September 2009 - Feature Articles
ASHRAE Journal - September 2009 - 19
ASHRAE Journal - September 2009 - 20
ASHRAE Journal - September 2009 - 21
ASHRAE Journal - September 2009 - 22
ASHRAE Journal - September 2009 - 23
ASHRAE Journal - September 2009 - 24
ASHRAE Journal - September 2009 - 25
ASHRAE Journal - September 2009 - How High Can You Go? Building Height and Net Zero
ASHRAE Journal - September 2009 - 27
ASHRAE Journal - September 2009 - 28
ASHRAE Journal - September 2009 - 29
ASHRAE Journal - September 2009 - 30
ASHRAE Journal - September 2009 - 31
ASHRAE Journal - September 2009 - 32
ASHRAE Journal - September 2009 - 32a
ASHRAE Journal - September 2009 - 32b
ASHRAE Journal - September 2009 - 33
ASHRAE Journal - September 2009 - 34
ASHRAE Journal - September 2009 - 35
ASHRAE Journal - September 2009 - 36
ASHRAE Journal - September 2009 - 37
ASHRAE Journal - September 2009 - Lab for Learning
ASHRAE Journal - September 2009 - 39
ASHRAE Journal - September 2009 - 40
ASHRAE Journal - September 2009 - 41
ASHRAE Journal - September 2009 - 42
ASHRAE Journal - September 2009 - 43
ASHRAE Journal - September 2009 - Solar Hot-Water Heating System: Lessons Learned
ASHRAE Journal - September 2009 - 45
ASHRAE Journal - September 2009 - 46
ASHRAE Journal - September 2009 - 47
ASHRAE Journal - September 2009 - 48
ASHRAE Journal - September 2009 - 49
ASHRAE Journal - September 2009 - 50
ASHRAE Journal - September 2009 - 51
ASHRAE Journal - September 2009 - 52
ASHRAE Journal - September 2009 - 53
ASHRAE Journal - September 2009 - 50th Anniversary—Low Pressure Steam Heating Systems
ASHRAE Journal - September 2009 - 55
ASHRAE Journal - September 2009 - 56
ASHRAE Journal - September 2009 - 57
ASHRAE Journal - September 2009 - 58
ASHRAE Journal - September 2009 - 59
ASHRAE Journal - September 2009 - 60
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ASHRAE Journal - September 2009 - 69
ASHRAE Journal - September 2009 - 70
ASHRAE Journal - September 2009 - 71
ASHRAE Journal - September 2009 - Building Sciences
ASHRAE Journal - September 2009 - 73
ASHRAE Journal - September 2009 - 74
ASHRAE Journal - September 2009 - 75
ASHRAE Journal - September 2009 - 76
ASHRAE Journal - September 2009 - 77
ASHRAE Journal - September 2009 - 78
ASHRAE Journal - September 2009 - 79
ASHRAE Journal - September 2009 - 80
ASHRAE Journal - September 2009 - 81
ASHRAE Journal - September 2009 - Products
ASHRAE Journal - September 2009 - 83
ASHRAE Journal - September 2009 - Emerging Technologies
ASHRAE Journal - September 2009 - 85
ASHRAE Journal - September 2009 - 86
ASHRAE Journal - September 2009 - 87
ASHRAE Journal - September 2009 - 88
ASHRAE Journal - September 2009 - 89
ASHRAE Journal - September 2009 - People
ASHRAE Journal - September 2009 - 91
ASHRAE Journal - September 2009 - 92
ASHRAE Journal - September 2009 - Classified Advertising
ASHRAE Journal - September 2009 - 94
ASHRAE Journal - September 2009 - 95
ASHRAE Journal - September 2009 - Advertisers Index
ASHRAE Journal - September 2009 - Cover3
ASHRAE Journal - September 2009 - Cover4
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