Closed-Loop Waste Energy Systems in Bakeries

Closed-Loop Energy Systems

Typical baking processes require various thermal heat exchanges – heating or cooling – used in sequence or simultaneously.  Significant potential exists to reuse these process thermal waste streams.  A Closed-Loop Waste Energy System (CLWES) greatly enhances facility sustainability providing both energy and carbon footprint reductions. Capturing and re-purposing thermal waste streams into a sustainable energy source capable of supporting various production processes will significantly reduce energy spend, shrink facility carbon footprint, and assist you in reaching your sustainability objectives with a positive return on investment.

Baking Closed-Loop Waste Energy Flow Chart Diagram

Baking Closed-Loop Waste Energy Flow Chart

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Maximizing waste energy recycling investment requires assessment of many factors; production requirements, waste heat sources available, existing capital equipment and operational cost, annual production hours, and type of thermal energy required for each process. CLWES capitalize on the synergies which exist between the various load processes.  When opportunities are available a “load balancing” component is incorporated into the design to offset the waste stream allowing process demands to be satisfied with little or no new energy input.

Baking Closed-Loop Waste Energy Schematic Image

Baking Closed-Loop Waste Energy Schematic

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Significantly reduce energy consumption by utilizing waste heat to power thermal processes. Electrical, Gas, and City Water savings can provide a rapid return on investment generating a positive cash flow depending on geographic region, hours of operation, and process load requirements.
System utilizes waste heat from large industrial ovens, oxidizers, or other waste heat sources currently being discharged directly to atmosphere.  As part of an intelligent facility architecture and waste heat streams available, systems have the capability of satisfying both hot and cold thermal process requirements from make-up to the freezers.
Many organizations currently purchase or will be required to do so in the future, carbon offset credits. The amount of credits purchased is directly correlated with facility energy usage and carbon “footprint”. Recovering existing thermal waste energy and reducing energy consumption lowers carbon credits purchase requirements by reducing facility electricity usage which may be generated by coal, oil, or natural gas.

Immediate returns are possible in most new facility installations.  Energy savings provides positive cash flow in most retrofit applications depending on full time process load requirements.  Additional utility or government incentives may be available to offset initial capital investment.

Sustainability Investment

 Properly utilized this “recycling” of process waste provides an immediate energy savings and if incorporated in initial designs may reduce capital investment. Waste heat can be used to create low temperature refrigeration, process heating to eliminate steam boiler requirements, or even generate electricity onsite. In existing facilities our “Pathway to Sustainability” solutions evaluate numerous technologies on a “cost to benefit” ratio providing you the opportunity to phase in facility initiatives over an extended period of time without altering long term capital budget schedules. This “Pathway” provides a catalyst for implementing future sustainable “Zero Energy” technologies starting with a lower initial investment.

Download informational brochure in PDF format

Please contact us if interested in learning more about Closed-Loop Waste Energy Systems from Air Management Technologies.

Atmospheric Molds Control

Atmospheric Molds Control

eurotiumSummer and fall present the greatest challenges in preventing mold spore contamination at North American food processing facilities.  Annual mold complaints typically spike during the warmer and more humid months of the year when conditions are ideal for microbial growth.  With reported spoilage rates approaching 5% seasonally in some facilities, mold contamination may create a quality problem resulting in excessive product rejection, reduced shelf life, and negative feedback from consumers.  Elimination of mold spores in a food production facility is not practical and would be a monumental achievement.  Instead product contamination mitigation utilizing a system of measures working in tandem is required to achieve best results.

While critical sanitation alone cannot prevent atmospheric molds from landing on product.  Ninety-five percent of the time goods may be susceptible to contamination is during the cooling and conveying process after leaving the ovens or fryers where any mold spores present may land on product.  A primary measure is enclosing cooling conveyors and where possible providing a filtered air supply to capture most of the spores.  Most mold spores are at least 1-micron or larger in size existing primarily in the 3 to 10 micron range. If your objective is to reduce mold spores by ninety percent, a filter should be selected based on a particle size of 3-10 micron at 90% efficiency.  Synthetic materials should be selected as a preventive measure against potential mold growth in areas with moist air streams and high relative humidity which may create food safety concern.

The best enclosure and filtration systems are of little value if the space is operated in a negative pressure drawing molds or other airborne contaminants into the enclosure.  Enclosed conveyors such as spiral coolers should be slightly pressurized with either filtered outside or conditioned plant air with gentle relief through conveyor openings acting as an indirect source of plant make up air.  One of the key developmental requirements of our proprietary Spiral Product Conditioning System in 1999 was to help bakeries address mold exposure.

Caution should be heeded to not automatically select the highest level of filtration.  Filtration efficiency should be based on tolerance levels of each ventilated space as there are several associated costs.  Filter media price, energy consumption changes, and potential degraded system performance must be considered in a cost to benefit ratio prior to selection for existing equipment. Additionally always consult a qualified air filtration specialist or mechanical contractor familiar with your equipment and ASHRAE guidelines prior to altering MERV ratings.

Please contact us if interested in learning more about reducing mold spore exposure in your production space.


Central Electric Panel Cooling

Central Electric Panel Cooling

Image - Electrical PanelSelf-contained air conditioning units mounted on electric panels have long been a source of frustration due to their excessive energy consumption, high maintenance requirements, and questionable reliability.  Additionally since equipment is located in production space where high dust concentrations and excessive ambient temperatures may be present, potential exists for the sensitive components inside the enclosure to be damaged.  Air Management Technologies has developed a solution utilizing a Central Electric Panel Cooling System by providing conditioning equipment outside the hostile environment.  Typical return on investment is usually less than 4-years considering operational expenses and system benefits.

Central Panel Cooling Systems enjoy several distinct advantages over traditional self-contained electric panel mounted air conditioning units.  A small diameter high velocity round duct minimizes exterior surface area reducing sanitation requirements.  The duct supplies conditioned air into the panels which contain an exhaust relief to production space.  Our design maintains a positive pressure inside the panel enclosure decreasing potential for dusts to accumulate on the electronics while providing an indirect source of makeup air inside the facility.  Balancing dampers are installed at each panel location permitting adjustments to maintain proper temperature.  Depending on application sensitivity motorized dampers and panel temperature sensors may be installed providing precise environmental control.  When integrated into a central facility control system sensors can detect irregular operations triggering alarm notifications to key personnel.  Early notification significantly reduces risk of panel failures resulting in expensive electrical components replacement and lost product line operation.

Reductions in panel cooling operational and maintenance costs are achieved by leveraging the efficiencies of a central unit compared to multiple self-contained panel coolers.  Energy savings may exceed 70% depending on geographic location since systems are engineered to utilize economized outside air when temperature and humidity conditions permit.  Savings are further maximized when utilizing variable speed fans, higher efficiency compressors, and the ability to maintain clean heat transfer surfaces by greatly reducing dusts infiltration and collecting deposits on mechanical equipment.  Remote equipment location may allow some preventive maintenance tasks to be performed safely during periods of line operation similar to other ventilation units.  With this configuration a facility has the option to outsource system maintenance tasks providing in-house staff a greater percentage of time optimizing process equipment.  A single central unit also permits installing higher efficiency air filters to the same environmental standards as other ventilation equipment.  Proper filtration further reduces potential for dusts to be supplied into the panels by the cooling equipment itself, a common occurrence with low efficiency permanent metal filters supplied by the panel cooling manufacturer which may allow significant bypass.

Opportunities exist to provide central panel cooling systems during new construction or electric panel retrofits.  Retrofits can be challenging due to existing panel spacing and conflicting plant utilities.  If considering a retrofit project it please contact us early to see if these challenges can be alleviated providing a greater return on investment.  Please contact us if interested in securing an estimate for a central electric panel cooling system for your food processing facility.


Chemical vs Natural Refrigerant Choices

Chemical vs Natural Refrigerants

Rapidly changing environmental regulations have caused industry to struggle when evaluating the choice between chemical or natural refrigerants in process cooling applications. In the United States the Clean Air Act first phased out CFC and later HCFC chemical refrigerants citing their ozone depletion potential. In response to these mandates and increasing corporate environmental initiatives food processing facilities have seen a surge in use of natural based and newer HFC chemical refrigerants which contain no ozone depletion potential.

Now a new initiative being proposed by the EPA and already adopted in many European countries is elimination of the HFC refrigerants citing a high GWP – global warming potential.   GWP is a relative measure of how much heat a “greenhouse gas” traps in the atmosphere and has a value assigned based on equivalent amount of global warming potential in comparison with carbon dioxide.  An example of these ratings:

HFC-134a = 1,300

Carbon Dioxide = 1

Ammonia < 1


While it may appear to some the obvious choice moving forward would be the use of natural based refrigerants such as CO2 and Ammonia many variables must be considered.  Chemical based refrigerants will certainly remain common in comfort cooling applications and will also remain preferred in many industrial processes as well.  Some of the questions to consider:

  1. What is the process application?  Requirements for a meat processing facility with high cold storage requirements may yield different results than a bakery with a glycol refrigerant system.
  2. What is my refrigerant inventory?  Does it make sense to determine how many lbs of refrigerant will need to be managed and total cost per lb of ownership?
  3. Is there a safety and health concern?  Some organizations are comfortable utilizing ammonia with its increased health and flammability potential when compared to most common chemical based refrigerants while others are not.
  4. Do we have environmental liability?  It is uncertain at this time what if any environmental liability will be assessed on HFC losses into the atmosphere.  Ammonia has reporting requirements for systems exceeding 100 lbs.
  5. How does this affect my capital budget?  Initial capital cost of equipment associated with use of natural based refrigerants is typically greater than chemical based refrigerants.
  6. What are my operating and maintenance costs?  Who will maintain the refrigeration systems and what technical skills / costs are required?

Additionally technological advancements to make natural refrigerants more efficient and also ease ammonia safety concerns include introduction of cascade systems which use carbon dioxide as a secondary refrigerant and HFC or ammonia as the primary lowering total inventory requirements.  Commonplace in regions with strict GWP regulations such as Europe, equipment manufacturers are now bringing these products to the North American market.  One major manufacturer is introducing an ammonia packaged chiller suitable for bakery glycol refrigeration systems which also may be located outdoors bypassing the need for a tradition equipment room.

We will provide more detailed insight on the various topics outline in future articles.  In the meantime if you have a more immediate question please feel free to contact us.


Compressed Air Energy Savings

Compressed Air Energy Savings

Quincy-QGV[1]While compressed air systems are an essential workhorse in most industrial facilities, they also carry the distinction of being one of the largest consumers of electricity.   Opportunities for compressed air system optimization are so significant the US Department of Energy has a dedicated website outlining methods for reducing their energy consumption. One area with high potential financial returns in bakeries and food processing facilities is utilization of the substantial waste heat streams generated by both the compressors and associated dryers, which is typically discharged outdoors (or in some cases air conditioned!)

Consider several potential uses for optimizing waste heat.  In northern climates each 100 brake horsepower air compressor has the potential to heat ten thousand square feet of area or preheat roughly 5,000 cfm of makeup air thereby reducing natural gas or electric space heating consumption.  Other geographic regions may benefit from boiler feed-water heating or similar temperature thermal processes.  Properly designed and executed typical financial returns are approximately 20% or greater for retrofit applications with new installations providing a less than one year payback on investment.

Caution should be exercised when evaluating proposals for compressed air heat waste recovery.  We have observed many installations by others that have not reclaimed promised thermal energy or in many cases have significantly damaged compressors and dryers.  One of the most common examples is improperly connecting air distribution ducting to the equipment.  Air compressors and dryers are not designed to overcome much air resistance while rejecting heat generated during mechanical use.  The higher static pressure of duct work may limit or entirely prevent the equipment from effectively releasing this energy causing increased energy consumption, compressor overheating, and eventual mechanical failure.  If you have any concerns regarding compressed air systems waste heat recovery systems please contact us and we will be glad to assist in implementation.