What’s Old is New Again – CHP for the Masses

by Visitor crumpster ‎07-09-2009 09:13 AM - edited ‎07-09-2009 09:27 AM

Power Perspectives: Dick Crump

I've noticed lately that combined heat and power (CHP) has been getting a lot more attention in the news. The U.S. Department of Energy released a statement announcing the allocation of $156 million in project funding under the U.S. Recovery Act for CHP and related technologies. WIRED magazine is talking about it. You can even find it on YouTube.

Why should you do it?
Electricity generation is not necessarily an efficient process – as an example, traditional coal fired plants generally only convert about 30% of the potential energy of the fuel being used into viable energy. By utilizing the thermal energy, CHP packages typically achieve total system efficiencies of 70 to 80%, effectively lowering fuel consumption and reduced emissions compared with conventional separate generation of heat and power.

Uses for CHP
Recovered heat can be converted into useful thermal energy, usually in the form of steam or hot water, for use in nearby buildings or in a power plant itself. Uses include:
  • Space or domestic hot water heating
  • Seasonal cooling (by way of absorption chillers)
  • Desiccant dehumidification
  • Heat for light production processes
  • Process cooling

Economics of CHP
Heat recovery does not need to be that ambitious to have a meaningful, positive effect on project economics. Almost any installation can profit from a simple heat exchanger capturing low-grade heat from the engine coolant.

Consider a small or mid-sized manufacturer with an on-site generator set and a hot-water load amounting to roughly one-third of the heat recoverable from the engine cooling circuit. A heat exchanger in the engine cooling loop, with a thermostatically controlled diverter valve to regulate the flow to the in-plant load, could cost-effectively satisfy the hot-water requirement.

Today's financing vehicles provide alternatives to return on investment calculations based on simple payback alone. For example, traditional debt financing or leases can be structured with fixed monthly or annual payments costing less than the owner's net savings on energy. In this scenario, the owner sees immediate positive cash flow – a net reduction in operating expenses from the first month in service. Leased equipment has the added advantage of being classified as an operating, rather than capital, expense. This can help expedite management approvals and take the projects out of competition for capital. For more information on procurement and financing, the U.S. EPA has published a very informative guide.

Getting Started
Extensive information is available on the web regarding combined heat and power. I've listed a few links below:
Are you presently considering CHP? Are there other resources/partnerships that you've found especially helpful? Have you had success in CHP that you'd like to share? Please post below.
Message Edited by crumpster on 07-09-2009 09:27 AM

by Visitor nagelgr
on ‎07-14-2009 10:10 AM
Caution when using CHP or heat recovery for watermakers!  Several of Caterpillar enignes will use a combined cooling system.  With todays emission regulations this has required very cool system operating temperatures which can reduce the available heat for recovery to a small portion of the total heat the engine is producing.  To correctly use heat recovery the circuit should be kept separate to be able to capture all of the high temperature cooling circuit.  For some enignes like the C280 there are "Watermaker cooling connections" which are available from the price list which can be used with the combined cooling circuit to recover all of the high temperature circuit heat.  There are some combined cooling systems like the 3500B Marine price list front mounted heat exchanger option which uses the aftercooler water to cool the jacket water circuit.  This system should not be used if doing heat recovery.  There is a DTO option for part number LA8025 which can be used instead and can be provided with watermaker connections for heat recovery.  The 3500C EPA Tier 2 Marine products offer a Separate circuit front mounted heat exchanger that can be provided with water maker connections as well with a DTO request through the ASC.   Sincerely,  Greg Nagel
by New member elaslugger
on ‎12-22-2010 10:28 AM

I designed and installed heat exchangers on 3 Cat 3304 diesel engines in a remote generating plant site. Only one engine is normally on line. All switching is done electronically to eliminate backflow to adjacent engines and heat exchangers. The system uses properly size exchangers with AMOT valves. Pretty simple, yet quite effective. System heats a shop of about 3,000 square feet (floor heat) situated about 300 yards from the generating plant.


My next objective is to harness the lost BTU’s exiting through the exhaust system. If anyone out there can point me in the right direction to find a heat exchange that can be incorporated through the exhaust system, it would be much appreciated. Thank you. Vern F.

by Visitor awaisgct
on ‎12-23-2010 04:55 AM

hi elaslugger tell me about tarbocharger of cat 3516b

by Visitor awaisgct
on ‎12-23-2010 04:56 AM

hi elaslugger tell me about tarbocharger of cat 3516b my e-mail address is awaisgct@gmail.com

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