Loading...
HomeMy WebLinkAbout2010-08-18 PACKET 08.A.REQUEST OF CITY COUNCIL ACTION COUNCIL AGENDA MEETING ITEM # DATE 8/18/10 , PREPARED BY Public Works Les Burshten ORIGINATING DEPARTMENT DEPARTMENT HEAD COUNCIL ACTION REQUEST Consider authorizing staff to purchase and install electronic infrared bleacher heat to the south rink mezzanine. STAFF RECOMMENDATION Authorize staff to purchase and install electronic infrared bleacher heat to the south rink mezzanine. BUDGET IMPLICATION $10,280 BUDGETED AMOUNT ACTUAL AMOUNT ADVISORY COMMISSION ACTION ❑ PLANNING ❑ ❑ ❑ ❑ PUBLIC SAFETY ❑ ❑ ❑ ❑ PUBLIC WORKS ❑ ❑ ❑ ❑ PARKS AND RECREATION ❑ ❑ ❑ ❑ HUMAN SERVICES /RIGHTS ❑ ❑ ❑ ❑ ECONOMIC DEV. AUTHORITY ❑ ❑ ❑ ❑ ❑ ❑ ❑ Y�117i7"III�LHZiZ�I /Ii•I�� ® MEMO /LETTER: ❑ RESOLUTION: ❑ ORDINANCE: ❑ ENGINEERING RECOMMENDATION: ❑ LEGAL RECOMMENDATION: ❑ OTHER: C: \Documents and Settings \nbelsoamper.CITYHALL \Local Settings \Temporary Internet Files \Content.Outlook \7M8RJGDE \City Council Action Form - Mezz Heat.doc To: Honorable Mayor and City Council From: Zac Dockter Date: August 11, 2010 Subject: South Rink Viewing Gallery Heating The ice arena locker room construction project has been progressing as planned and certainly appears to finish under budget due to a favorable bidding environment. At this time staff is recommending the installation of electric infrared heating units to the mezzanine viewing gallery. The heat would bring the winter temperature from as low as 30 degrees to a more comfortable 70 degrees for the spectators. Similar to the installation of the west rink bleacher heat, the customer experience would be greatly improved. Attached is a memo submitted to council in 2009 which details how and why infrared heat should be considered an asset to the Cottage Grove Ice Arena. The total cost of the heating units installed would be $10,280. Expected annual energy costs to generate the heat are $1,000. There may be some offsetting revenues by creating a more user friendly facility but projecting that number would be very difficult at this time. Without a doubt the largest complaint regarding the south rink is the temperature for the spectators. Those spectators more often than not are the paying customers for the youth on the ice. Enhancing the viewing experience for those customers should be considered a priority. In the 4/22/10 locker room construction memo to council, staff estimated a $175,000 construction cost for the project. The current estimate including bleacher heat is as follows: Construction Contracts $145,241 Protective Netting $4,152 Plumbing $4,500 Infrared Heating $10,280 TOTAL $164,173 City of Cotta Grove Minnesota To: Ryan Schroeder From: Zac Dockter Date: 2/18/09 Subject: Ice Arena Heating for West Rink Introduction When designing the new Cottage Grove Ice Arena, there was undoubtedly much emphasis placed on the refrigeration and dehumidification systems to provide the best ice skating experience possible to our skaters. What was explored but removed as an alternate was the need to provide supplemental heat to spectators in the new west rink. Many people who will not set foot onto the ice surface commonly frequent the Cottage Grove Ice Arena. This includes spectators, family members, spouses, and friends of the players and skaters. The comfort of paying parents and /or spectators could be considered as critical as the amenities provided to those using the ice. After all, it's often the parents and spectators who will develop and mold public opinion of the facility. Providing reasonably warm viewing areas are nearly as important as making good ice or maintaining clean restrooms in portraying the Cottage Grove Ice Arena as a state of the art facility. After a season of operating the new ice arena, the primary complaint (of which there have been few complaints so far) has been directly attributed to the temperatures for spectators in the west rink. Heating Options There are essentially two heat source options available in the ice arena industry. The options are forced air heat or infrared heat. With the development, technological improvements and efficiencies of infrared heating, it is very rare to find ice arenas that continue to use forced air as a heat source in rink areas. The exception to the case is very large facilities such as the Xcel Energy Center and college hockey arenas where spectator areas are simply too large to be able to provide for infrared heating due to the proximity of the ceiling to the spectator areas. In these large arenas the only real option to providing comfort to the spectators is to use forced air heaters and heat the entire arena environment. This certainly creates inefficiencies in utility consumption by adding additional load to the refrigeration system. But, it allows the arenas to keep spectator viewing lanes wide open by eliminating ceiling clutter and also provides uniform heating to all users of the facility. In an application such as Cottage Grove's, forced air heating should be considered an inefficient means to providing heating comfort and will not be recommended as an option in this memo. In average size ice arena facilities such as Cottage Grove Ice Arena, spectator areas are consolidated to specific areas of the rink which reduces the need to heat the entire facility to provide comfort to spectators. Gas -fired infrared heaters offer a solution to the problem of strategically heating spectator zones without heating the entire rink area. These heaters offer many advantages including high comfort levels and low operating costs. The theory of infrared heating in simple terms is to mimic the best natural heat source we know of; the sun. Even when it's cool outside, we feel much warmer soaking in the sun's direct infrared rays. By mimicking the sun's infrared rays, gas -fired infrared heaters can provide heat that is absorbed by people, flooring, and seating and directed to avoid heating delicate ice surfaces. Infrared heating offers a multitude of operational benefits including: 1. Fuel savings of 20 to 50% over forced air heaters 2. Flexibility: you place heaters only where needed 3. Modular design keeps capital costs low when compared to forced air heating 4. Zoned capability allows units to function together or independently 5. Condensation control help protect and improve environment 6. Superior comfort levels that allow people to move to /from the heat source as desired 7. Quiet and clean operation Infrared Heating Options There are two main types of infrared heaters: high- intensity ceramic heaters and low- intensity tube heaters. Although both types use natural gas combustion to generate infrared radiation, there are a number of important differences between the two. High - Intensity Infrared Heating With high- intensity heaters, gas is ignited on a ceramic refractory surface, which is heated to 1,800 degrees F and gives off an incandescent red glow. The compact box -like heaters discharge the products of combustion via vent through the roof. High- intensity heaters are more popular for spot or area heating on a smaller scale than the typical bleacher system. High- intensity heaters do require greater safety distance to combustibles and once again lose heating effect as the distance increases. These heaters are fairly bulky boxes which hang from the ceiling and do often times require many units to cover the bleacher areas which can lead to a cluttered ceiling and many cuts into the roof /wall for venting. As an example, Wayzata recently removed 24 units in their rink in favor of the tube system. I provide this information on Wayzata simply to emphasize the amount of units it may take to heat a bleacher area such as ours. Also, these systems do vent some combustible bi- products into the arena environment and can cause air quality concerns in an environment that is already heavily monitored and a concern in our industry. For these reasons alone, I would not recommend the high- intensity heating units for our application. Low - Intensity Infrared Heating In low- intensity tube heating, flame and hot combustion gases from a burner box are either pulled through steel tubes by a vacuum fan (negative pressure) or they are pushed through by a blower motor (positive pressure). The steel emitter tube temperatures will peak around 1,000 degrees F and decrease over the length of the unit to around 200 degrees. Combustion gases are vented outside. Units are typically installed in 30 foot lengths. Low - intensity systems are installed in a manner that is non - invasive to the site lines, minimizes ceiling clutter and cuts into the roof /wall for venting. However, the further the heaters are placed from the area needing heat, the lower the heating effect. In applying the low- intensity heating principles to the Cottage Grove Ice Arena application, the primary design characteristics are derived in identifying the specific areas we wish to heat. The west rink bleacher area spans approximately 180 feet with an additional 30 feet of space at the entry and the west viewing area. An informal estimate of 75% of all spectator usage of the bleachers takes place in three key areas. Those areas are: 1. The center two sections of seats 2. The upper two rows of seats /walkway 3. The entry area Both low- intensity infrared heating models can target these key areas and provide comfort to spectators. However, only the positive pressure system can be installed in phases if the city desires to do so. As an example, the positive pressure system could be installed in three phases over multiple years. When applied correctly, both low- intensity infrared heating systems will provide a significant increase in temperature to the objects below them which may include spectators, seats, floors and railings. The west rink of the Cottage Grove Ice Arena currently averages temperatures between 35 and 50 degrees dependent upon outside conditions. Using an average of a 40 degree temperature throughout much of this past winter without any heat sources, the installation of an infrared heating system should provide a much more comfortable temperature range of 60 to 80 degrees for spectators. Low - Intensity Infrared Heat Disbursement A large difference between the positive and negative pressure systems is the disbursement of the heat. The negative pressure system is a single linear tube in which four units will be sequenced in a row and will work as one complete system. This system will have varying levels of heat provided based location in respect to the burner. It could be expected that the 15 feet closest to each burner will experience temperatures around 80 degrees whereas the 15 feet furthest from the burner will experience temperatures closer to 60 degrees. The negative pressure system uses a U- shaped tube pattern to more evenly distribute the heat. The heat that is lost on the last 15 feet of tube (similar to the negative pressure system) is wrapped in tight with the hotter first 15 feet of tubing so the net result is that the spectator will not notice a difference in any particular segment of the heating unit. The negative pressure system will bring a typical 45 degree temperature to a more comfortable 70 degree temperature the entire length of the system. The negative pressure system is also installed as a modular system so that each 30 — 40 foot section is installed completely separate of one another. This provides the city the ability to install and /or operate the system in phases to save on capital and operational expenses. Attached are two design concepts to give an image of how each low - intensity system would lay out and how it will impact the comfort level of the seating areas. It should be noted that all of these estimations will vary based on the exact location of the system. The primary factor in the transfer of heat is the proximity of the heat source to the bleachers. For every additional foot the unit is placed away from the bleachers, 2 -3 degrees of temperature will be lost at bleacher level. So, staff and the contractor will have to determine the optimal height of the system to maximize the heat source but to minimize the loss of any site lines, reduce safety concerns and minimize damage potential from flying pucks. Current /North Rink Heating System As there has been discussion in the past regarding inadequacies of the north rink heating system, it seems appropriate to analyze this facility and equipment as well. Currently the north rink is equipped with a low- intensity infrared negative pressure system. Applying the aforementioned principles of a negative pressure system, we currently maintain a temperature of about 60 degrees in the areas near the burners and 50 degrees away from the burners. This is an improvement to the control temperature of 35 degrees with no heating source. In part, the reason we have not been able to achieve the 70 degree temperature estimates for the new west rink system has simply been the location height of the system in its relation to the arched roof and site lines. So, although the total comfort level and disbursement of heat is not ideal on the north rink, I don't believe the investment justifies the gain at this time. The heating units and vacuum pump are still in good condition and I would project a good ten years or more of life from those key pieces of equipment. Operational Expenses Operational expenses related to each of the low- intensity infrared heating systems can be estimated as follows: 175,000 BTU = 1.75 therms 1.75 therm x .90 = $1.58 per hour. Using the above rate, total energy consumption per year can be estimated at approximately $3,160. This number is based on running the system for 2,000 hours per year which in my experience is a conservative estimate. However, the cost of a natural gas therm has ranged from $0.65 to $1.20 over the past two years so variations in gas costs will play a role in the final operation costs as well. Often times, heat is used only for games or other large spectator events. Currently our staff is directed to turn the north rink units on during games or when large groups are in the stands. Otherwise, they are only turned on upon request. The major advantage of infrared heating systems is the ability to turn the system on and off at any moment to better manage utility consumption. The system provides heat within minutes of activating the burners so there is no need to keep units running to minimize heat loss. Capital Investment Pricing estimates for installed low- intensity infrared heating systems are as follows: Negative Pressure Complete System = $35,000 Positive Pressure Complete System = $27,000 Positive Pressure System Phase I (over center sections of bleachers only) _ $11,500 Recommendation It is my recommendation to purchase and install a positive pressure low- intensity infrared heating system for the west rink bleachers of the Cottage Grove Ice Arena. Based on availability of funds, either a complete or phased system approach would be an acceptable.