Plant Services - November 2007 - (Page 57)

EFFICIENCY Compressors the water is about 4,980 lbs per hr. e speciﬁc heat of water is about 1 Btu/lb-°F, and for air is about 0.24 Btu/lb-°F. at means that the ﬂow of air has the minimum product of speciﬁc heat and mass ﬂow, or about 109 Btu/hr-°F. Multiplying this value by the eﬀectiveness (0.70) and the temperature diﬀerence (250°F-70°F) gives the estimated heat recovery rate, 13,730 Btu/hr. Capital costs to implement a compressed air heat recovery system are variable, but the payback period usually is attractive. A quick scan of 25 air compressor heat recovery projects detailed in the Rutgers Industrial Assessment Center (IAC) database indicates an average cost of about $10,400 and average annual savings of about $11,100. Payback periods for the sampled projects averaged about one year with a range from ﬁ ve years to ﬁ ve weeks. The supermarket e ect Anyone who needs a winter coat when grocery shopping in August or September can get behind the idea of supermarket refrigeration heat recovery. Frequently, it turns out that the interaction of the refrigerated display cases and the store’s HVAC system produces heating loads on the HVAC during the fall, winter and spring. ese loads can be partially met by the heat being rejected from the refrigeration system. Energy available for reclaim consists of the display case refrigeration loads and the work of compression. Typically, during normal compressor operation, the pressurized refrigerant ﬂows directly to the condenser. When space heating is called for, a three-way valve routes the gas ﬂow to a coil located in the HVAC air handler. Both desuperheating and condensation of the refrigerant gas occurs in the heat reclaim coil. e refrigerant leaves the reclaim coil and ﬂows to the condenser where there is additional heat rejection. It’s estimated that reclaiming refrigeration system heat can have a payback period ranging from about two to four years. Costs for adding heat reclaim to a refrigeration system are estimated at between $150 and $200 per ton of refrigeration system capacity. Supermarket refrigeration system heat recovery is becoming a relatively well understood system design, so implementation is more plug-and-play than air compressor heat recovery. Typically, heat is recovered to provide Shaft alignment in a Flash® More comfortable dockers New! Offset shaft alignment in a Flash. A new hardware+software expansion kit is now available for the XA that allows quick and easy alignments of offset (cardan) machine shafts. The system incorporates on-screen Flash® animations that actually walk the user through the offset shaft alignment process! Quickly align your offset shafts to reduce wear on gearboxes, bearings and offset joints. Figure 2. Ducted heat from a nearby compressor improves working conditions at this loading dock. www.vibralign.com 800-379-2250 Flash is a registered trademark of Adobe Systems Incorporated. N .PLANTSERVICES. 57 http://www.vibralign.com http://www.PLANTSERVICES.com

Table of Contents Feed for the Digital Edition of Plant Services - November 2007

Plant Services - November 2007 Contents New Tools Letters Let Us Know Where to Put the Gas Up and Running How are you Fighting Crisis? What Works Why is the Best Practice Transfer so Hard? Who are you Going to Call? Chained to Power Mobile Mindset Making Money in the Lube Lab Grabbing a Moving Target Bagging the BTUs Keeping Mellow Preserving Health and Safety The Power of Reliability Excellence

Plant Services - November 2007

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.