heat pump newsletter 1 - Hexag1热泵通讯网.doc

HEXAG NEWSHEXAG NEWSThe Newsletter of the Heat Exchanger Action GroupIssue 18, July 2003The Newsletter of the Heat Exchanger Action GroupEDITORIALFollowing on from earlier submissions to Future Energy Solutions and thence to the Carbon Trust, I am now preparing a short note which it is hoped will form the basis of a case for the inclusion of Compact Heat Exchangers on the Enhanced Capital Allowance (ECA) List. Working with Future Energy Solutions and a Focus Group which includes a number of HEXAG members (and others), it is intended by October 2003 to have a Case prepared which will be submitted to Government for approval.Among the more difficult aspects of the preparation of the Case are the definitions of eligibility for the type(s) of Compact Heat Exchangers to be recommended, and the test standards. HEXAG members who belong to industrial bodies who have an interest in compacts, including manufacturers associations and those who organisations participate in relevant Climate Change Levy Agreements, are invited to contact me during the next 4 weeks to express their interest.Initially, we are concentrating on the process industries. Another exercise (see minutes of the last HEXAG meeting at Brunel Bob Tuckers talk) is looking at heat recovery in buildings.I hope that this will ultimately benefit the heat exchanger industry, and encourage users to invest in compact heat exchanger technology.David Reay HEXAG Co-ordinator,PO Box 25, Whitley Bay, Tyne & Wear, NE26 1QT, UK. NE26 1QT. Tel: 0191 251 2985. Fax: 0191 252 2229. Email: DARHEXAG Web Site: www.hexag.hw.ac.ukIN THIS ISSUE*Editorial * MTU Clears the way for heat exchanger tests * Ashe Morris constant flux reactor latest data * Self-cooling drinks can * Steam compression heat pump project funded by the Carbon Trust * Report- Fifth International Conference on Boiling Heat Transfer * EPSRC Heat exchanger and heat transfer projects * Job opportunities at Chart Heat Exchangers * Useful web sites * Recent Literature & Patents * Forthcoming Events/Calls for Papers * HEXAG Help Line *The next HEXAG MeetingMTU Clears the Way for Heat Exchanger TestsMuch in the press concerning aviation these days covers the environmental problems created by gas turbine engines, and the suggestions that airlines should pay tax on aviation fuel! The sector is, however, well aware of the need to minimise emissions from engines, and heat exchangers have an important role to play in this, as is evident from the article below, based upon a news item in Flight International, 24-30 June 2003:MTU, the German high technology company, has produced the first unit for a demonstration heat exchanger for the CLEAN (Component validator for environmentally friendly aero engines) turbofan (large gas turbine) programme. Testing of the heat exchanger is scheduled for 2004 in a high altitude simulator in Stuttgart.The heat exchanger, effectively a tubular recuperator with oval or aerofoil-shaped tubes to minimise pressure drop, (probably like the tubes GEA used to market for large heat exchanger duties Editor), has a design thermal efficiency of 58%, (HEXAG News readers may like to compare this with the R-R recuperator we saw at Ansty some years ago). The potential fuel saving based upon this efficiency could be up to 20%, according to Klaus Steffens, Chief Executive of MTU Aero Engines. The unit has 7000 m of tubing, but the overall volume and other dimensions are not revealed.The aim of the MTU work is to use a combination of compressor flow heating (with the recuperator using exhaust gases) and intercooling to improve compressor efficiency without increasing compressor work. The other lead patner is SNECMA in France, and it is hoped with the CLEAN turbofan to cut CO2 emissions by 20% and NOx by 80% Entry of the concept into service could be around 2015. It would be interesting to know if the Boeing 7E7 will be using recuperated engines - I have seen no reference to them in current literature on the proposed airliner).+ Ashe Morris Ltd 2003Ashe Morris Constant Flux ReactorThose of you at the Nottingham HEXAG meeting last year will recall the talk by Robert Ashe of Ashe Morris Ltd., a design company, when he introduced us to an interesting new concept, the variable area heat exchanger. He described this as a different way of building and using heat exchangers, and illustrated it with an example for controlling the temperature of a chemical reactor, with a 10 kW heat load.Subsequently, some research has been successfully completed, and the conclusions resulting from the tests completed in June 2003 are given below.Conclusions Constant flux delivers unparalleled performance Very accurate heat measurement (accurate to within 0.1% in some tests) Precise temperature control under the most severe load changes (generally better than 0.10C) Good power monitoring with further improvements expected Fast heating and cooling with no overshootConstant flux is a much simpler calorimetry technique No time consuming set-up (just turn on and use) No calibration (other than for background system losses)Constant flux offers a fully scalable solution For the first time, accurate calorimetry can be utilised through scale-up and manufacturing Accurate on-line monitoring can be used to improve process performanceFor further information, Contact: The test data are available on the HEXAG web site as a .pdf file for downloading.+SELF-COOLING DRINKS CANThere have been many attempts to cool drinks cans using a self-contained chilling system. Similarly, methods for heating food packages also exist. However, since the curtailment of direct rejection of refrigerant gases (CFs, HCFCs and more recently HFCs, the latter being a strong greenhouse gas) to the atmosphere, Joule-Thompson type coolers have been frowned upon. Our cool drinks are best obtained from a refrigerator!Now (The Engineer, 10-23 Jan., 2003) it is revealed that desiccant-type coolers can be built in to cans, to provide cooling of the drink. At the time of writing, it was proposed to test the container by supplying samples to a team taking part in the Paris-Dakar motor rally, followed by consumer trials late in 2003.ThermaGen, the French company (see www.T), specialises in evaporative cooling systems, and the ice-shake can cool a 30 cl drink to 15oC in less than three minutes. For desert use this may be fully adequate as the drinks may be initially at 40oC or more. However, for domestic use we would prefer temperatures rather less than 15oC for cool lager! The cooling system comprises a heat exchanger (a tube with longitudinal fins projecting into the drinks compartment), a desiccant similar to a clay to absorb water, and 1 cl of water. The desiccant sustains the cooling reaction, the heat being removed from the drink via the heat exchanger immersed in it.Illustration on the company web site suggest that the cooling system effectively doubles the volume of the can, and of course will add to the cost. It is claimed that the system can be recycled, however.*Steam Compression Heat Pump ProjectFunded by The Carbon TrustIntroductionSteam is used throughout the process industries in the UK as a convenient source of heat. The usual source of this steam is a centralised boiler plant containing a medium pressure boiler burning fossil fuel, and operating at a pressure of 8 to 10 bar gauge. At the point of use the steam pressure is then frequently reduced to between 0.5 and 2.0 bar gauge.Although the nominal efficiency of steam boilers typically used in the UK can be greater than 80% at full output, the efficiency of heat delivery to the process may be much lower. Start-up, shut-down, distribution and other losses, have to be taken into account, and also the effects of part load operation.For many steam-using sites, the boiler plant consumes the major part of all fuel purchased, and steam raising accounts for a large portion of the total energy use and greenhouse gas emissions. There is therefore considerable benefit to be derived by improving the efficiency with which low pressure steam is provided for process applications.Steam Compression Heat PumpsThere are many working examples of open cycle water vapour heat pumps, and the technique they frequently employ is Mechanical Vapour Recompression (MVR).The first process plants of this type put into operation used gear-driven centrifugal compressors, based on designs used for gas compression which were both complex and expensive. Initial applications were therefore limited to relatively large duties, with power inputs to the compressor frequently in excess of 500 kW.Subsequently, other types of compressor such as Roots type blowers, screw compressors, and high pressure fans came into use, and this significantly increased the range of duties to which MVR was applied.Unfortunately, MVR has been perceived to be at best only marginally economical in the UK. The reasons for this include : The compressors are usually electrically driven, and the price of electricity relative to other fuels has proved a hurdle in some cases. UK businesses seek short payback periods on all equipment, regardless of the scale of the annual savings. A failure to appreciate the full range of benefits that will follow from the application of the technology at a particular site.Steam compression heat pumps have the potential to substantially reduce process energy usage with the attendant benefits of reduced primary energy inputs and carbon dioxide emissions. It is therefore very important that their use is objectively assessed on the basis of the equipment and systems that are or could readily be available.This ProjectThe main objective of the project was to investigate the use of steam compression heat pumps as a means of providing low pressure steam for process applications. The work has included an assessment of compressors and drive systems that are now actually or potentially available, and recent developments in the design of compressors and high speed motors. The steam input to the heat pump can be derived from a wide variety of sources, and those considered have included engine cooling water, hot effluents, and hot water produced in other processes. A further part of the project has considered economic factors such as capital and operating costs. The wide variation in duties and site conditions means that a detailed investigation into each application must be made in order to establish all the benefits that will result from a particular application of the technology. However, a simplified spreadsheet calculation for potential users has been developed, which allows an initial assessment of a particular application to be made.ConclusionsThere is now increased interest in the use of steam compression heat pumps for industrial applications in the UK. This is partly due to lower electricity prices, and partly because of energy efficiency targets forming part of Climate Change Levy Agreements. Additionally, the use of a heat pump will alter the balance between the various forms of energy used on site, which may be important when CHP systems are being considered.This project has shown that steam compression heat pumps can reduce energy consumption, operating costs, and carbon dioxide emissions. Large savings can be made when the steam input is derived from an otherwise waste heat flow. Additionally, development for steam compression applications of some of the compressors and drives now available has the potential to significantly reduce capital costs. This would greatly increase the number of uses for the technology.For further information please contact -Fred Brotherton, Beedes Limited, 01 444 250708 or fred.brothertonbeedes.co.uk+Report - Fifth International Conference on Boiling Heat TransferMontego Bay, Jamaica, May 4-8, 2003About 80 delegates attended the 5th ICBHT at the Sunspree Holiday Inn, Montego Bay, Jamaica, in early May. Some 50 papers and 12 Keynote Lectures were presented, and there was ample opportunity for discussion of all apects of boiling heat transfer, both in formal sessions and informally. All aspects of the subject were covered, with the emphasis tending towards the mechanisms and analysis of the boiling process. Not surprisingly, given the location of the conference, the US delegates provided the largest contingent of delegates with about 50 attendees. Some 15 Germans attended, while only the UK was represented by 3 delegates, reflecting the differential in research funding in this area. Notwithstanding, the conference had a truly international flavour and presented an excellent insight into the contemporary issues governing the state-of-the-art in boiling heat transfer. A programme, listing the papers presented is available at /ICBHT/agenda.asp and delegates have printed proceedings. Selected papers presented at the conference will be published in a special issue of the International Journal of Heat and Fluid Flow. HEXAG members requiring further information should contact P.A.Kewhw.ac.ukEPSRC HEAT EXCHANGER & HEAT TRANSFER CURRENT PROJECTSEmma Feltham of EPSRC has provided HEXAG with a listing of all current projects in heat exchangers (listed below) and heat transfer (a small selection listed below).This information is available on the EPSRC website (www.epsrc.ac.uk under the Grant Progress Checker http:/www.epsrc.ac.uk/website/gow/gowdefault.aspx?ZoneID=1&LozID=9 using a free text search for heat exchange or heat transfer). The data sent by Emma will also be available on the HEXAG web site.The project data are arranged as follows:Project TitleInvestigatorInstitution ValueStatusInnovations in Heat Recovery Systems for Tubular Heat ExchangersDr PW JamesUniversity of Plymouth154,759Asymmetric Radiant Fields & Human Thermal ComfortDr D FialaDe Montfort University63,057THE USE OF WINDOWS FOR PRE-HEATING VENTILATION TO BUILDINGSDr ME McEvoyUniversity of Cambridge36,991ROPA: ADVANCED COOLING TECHNIQUE FOR GAS-ASSISTED INJECTION MOULDED ARTICLESDr GF SmithUniversity of Warwick118,570CAPILLARY ASSISTED DIRECT-EXCHANGE WATER EVAPORATORDr HM SabirKingston University61,158OXYGEN ISOTAPE EFFECT IN THE NORMAL-STATE PSEUDOGAP OF HIGH-TC SUPERCONDUCTORSProfessor WY LiangUniversity of Cambridge9,058THE USE OF WINDOWS FOR PRE-HEATING VENTILATION TO BUILDINGSDr ME McEvoyUniversity of Westminster136,110SOOT PRODUCTION IN LAMINAR DIFFUSION FLAMES BURNING BLENDED FUELS AT ELEVATED PRESSUREProfessor JB MossCranfield University119,126THE INTERACTION OF HEATING AND COOLING SYSTEMS WITH THE NATURAL VENTILATION OF BUILDINGSProfessor AW WoodsUniversity of Bristol137,729POLYMERIC HYDROPHILIC COATINGS FOR COMBINED HEAT-AND- MASS EXCHANGERSDr M NewboroughCranfield University182,401AUTOMATIC SYNTHESIS OF COMPLEX PROCESS FLOWSHEETS WITH COST AND NON-COST OBJECTIVESProfessor JW PontonUniversity of Edinburgh172,982STRUCTURE OF TWO PHASE FLOWDr RHS WintertonUniversity of Birmingham66,103STRUCTURES AND PROPERTIES OF NANOCRYSTALLINE IRON-RARE EARTH ALLOYS FOR HARD MAGNETIC APPLICATIONSProfessor HA DaviesUniversity of Sheffield121,281Total number of projects: 13Total value of support (UK ): 1,379,325*With regard to heat transfer, a selection of the 245 projects currently being funded is given below. See the web site at the beginning of this article for a full listing.FARADAY Fast Track Proposal - Vacuum Window Design Optimisation and Thermal Comfort ImplicationsProfessor PC EamesUniversity of Ulster113,303Faraday Fast Track: Control of heat transfer and airflow in multi-functional facades: a basis for design guidance for low-energy buildingsProfessor VI HanbyDe Montfort University131,938FARADAY FAST TRACK PROPOSAL: PRACTICAL MATHEMATICAL MODELS OF SCRAPPED SURFACE HEAT EXCHANGERSProfessor CP PleaseUniversity of Southampton101,761Heat transfer and fluorine emissions from the mould in continuous castingProfessor KC MillsImperial College London252,559A Theoretical Investigation of Flow Boiling in Capillaries.Professor SK WilsonUniversity of Strathclyde137,414Turbulent Forced Convective Heat Transfer Over Vibrating Surfaces: An Experimental InvestigationDr E BenardQueens University of Belfast65,391Innovations in Heat Recovery Systems for Tubular Heat ExchangersDr PW JamesUniversity of Plymouth154,759THE RELATIONSHIP BETWEEN HEAT TRANSFER & AERODYNAMICS FOR FILM-COOLED AXIAL TURBINE TIP-CLEARANCE FLOWDr GD LockUniversity of Bath177,716HEAT TRANSFER IN GAS TURBINE COMBUSTORSDr AL HeyesImperial College London279,603+JOB OPPORTUNITIES AT CHART HEAT EXCHANGERSChart Heat Exchangers in Wolverhampton has two vacancies for chemical engineers:1) Projects Engineer: To be employed on the design, selection and application of plate-fin heat exchangers to meet customers specifications, taking into account process & mechanical requirements together with overall plant installation and operation. With growing experience, responsibilities will include providing the full technical & commercial tender followed up by customer visits and final contract negotiation.2) Applications Engineer: This position is for a chemical engine