| 61. |
- Berntsson, Thore, 1947
(författare)
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Future Prospects for Industrial Heat Pumps in Europe
- 1987
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Ingår i: IEA Heat Pump Conference - Heat Pumps: Prospects in Heat Pump Technology and Marketing. ; , s. Chapter 21, 303-324
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The future prospects for industrial heat pumps in Europe are discussed in terms of possible applications, types of heat pumps to use, present situation, economic aspects, and other aspects, such as environmental ones.It is shown that there is a large technical potentialespecially in the higher range of condensing temperatures, 120-160 DC. The technico-economic comparisons have shown that there is also an economic one, which, however, is much dependent on the future electric and fuel prices. These will also influence the types of heat pumps to use. Environmental aspects will also play an important role.The need for future R,D&D work includes development of better high-temperature heat pumps and system aspects, such as process integration studies to identify interesting applications.
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| 62. |
- Berntsson, Thore, 1947
(författare)
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Heat sources - technology, economy and environment
- 2002
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Ingår i: International Journal of Refrigeration, Elsevier Science Ltd and IIR.. ; 2002:25, s. 428-438
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Tidskriftsartikel (refereegranskat)abstract
- Heat sources for heat pumps in buildings as well as in industry are discussed. Furthermore, some environmentalaspects concerning choice of heat source are highlighted. Only systems for heat pumping are included, i.e. air-conditioning types which can also partly work as heat pumps are excluded. Recent heat pump installations in Sweden are mainly in small systems. Ambient air, exhaust air, soil and rock are the most common heat source types. Data on COP, investment costs, working fluids, present Swedish market etc. for these types of heat sources are given. Data on industrial heat pump installations in some countries and distribution of these according to heat pump type and industry sector as well as heat source temperatures are reported. Process integration aspects when choosing heat source size and temperature are also discussed as well as the relation between these parameters and the choice of heat pump type. Finally, the influence on the economy of the heat source temperature is presented. The cost-effectiveness of heat pumps for reducing CO2 emissions compared with other heating technologies is discussed. The main results are: (1) heat pumps can in many cases in the future contribute to a reduction of CO2; (2) there is a rather big difference, for larger systems a major difference, between the water-based and the ambient air-based heat pumps in terms of efficient reduction of greenhouse gas emissions.
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| 63. |
- Berntsson, Thore, 1947
(författare)
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Heat Sources – Technology, Economy and Environment
- 1999
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Ingår i: presented at the 6th International Energy Agency Heat Pump Conference 1999, Heat Pumps a Benefit for the Environment, Berlin, Germany, May 31-June 2, 1999..
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Konferensbidrag (refereegranskat)
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| 64. |
- Berntsson, Thore, 1947
(författare)
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Heat Transfer in a New Type of Heat Exchanger for Divided Solids
- 1979
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Ingår i: Powder Technology. ; 1979:22, s. 101-11
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Tidskriftsartikel (refereegranskat)abstract
- A new type of horizontal, rotating drum heat exchanger is described, which is intended for indirect heat transfer between two streams of solids or for indirect cooling or heating a stream of solids. The heat exchanger is baffled internally and the baffles have three purposes: a transport of the solids, enlargement of the heat transfer area and agitation of the particulate bed in order to achieve good mixing. Rates of heat transfer were measured for streams of four kinds of solids material: two types of sand, glass beads and steel shot. The rate of heat transfer-increased with increasing speed of rotation and fill of the particle bed. The mean particle diameter was the most important of the particle properties. Overall heat transfer coefficients were found to be higher than for most other types of indirect heaters and coolers for solids. A model of the heat transfer process is presented in which the whole resistance to heat transfer is assumed to be in the particle layers in the vicinity of the heat transfer wall. This resistance consists of two parts, one time-independent between the wall and the bed and one time-dependent in the bed itself. The model is shown to be capable of predicting the rates of heat transfer accurately.
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| 65. |
- Berntsson, Thore, 1947, et al.
(författare)
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Heat transfer of nonazeotropic mixtures in a falling film evaporator
- 1985
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Ingår i: ASHRAE:s Annual Meeting, Honolulu, 23-27 June 1985: - ASHRAE Transactions. ; 91:1, s. 1337-1350
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The evaporative heat transfer coefficient for nonazeotropicmixtures of R12 and R114 has been studied in a falling filmheat exchanger. The main aim with the project has been tostudy how the heat transfer coefficient is influenced bythe additional mass transfer resistance that is introducedwhen a mixture is used instead of a pure refrigerant.The test apparatus consisted of one tube, which was heatedfrom the outside and with the refrigerant forming a fallingfilm on the inside. The heating was done by a liquidflowing in an annular space countercurrently to the fallingfilm.From the results it can be concluded that the heat transfercoefficients for the mixtures at surface evaporation conditions are between the corresponding ones for the pure refrigerants at given Re numbers. This indicates that theadditional mass transfer resistance when a mixture is usedis small in a falling film at such conditions. This isprobably due to the small film thickness.The heat transfer coefficients versus the heat flux werealso measured. Again, the values for the mixtures at agiven'heat flux fall between the corresponding for thetwo pure refrigerants, both at surface evaporation andnucleate boiling conditions.
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| 66. |
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| 67. |
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| 68. |
- Berntsson, Thore, 1947
(författare)
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Hur skall industrins spillvärme utnyttjas på ekonomiskt optimalt sätt?
- 1988
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Ingår i: Föredrag vid konferens "Energiekonomi", Göteborg april 2008. ; , s. 14-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Industrin står för en stor andel av den totala energiförbrukningen i Sverige, I detta föredrag kommer olika möjligheter till tekniskt/ekonomiskt rationell energianvändning i industrin att diskuteras. Det kommer att visas att industriella energisystem bör ses som en resurs, även för samhället, i framtida investeringar för ett effektivare svenskt energisystem. Samarbete mellan industri och samhälle kan ske på ett rent ekonomiskt plan (samfinansiering, vinstdelning etc) eller på ett fysiskt plan (kommunuppvärmning med industriellt spillvärme etc). De rent ekonomiska samarbetsmöjligheterna är de intressantaste och har den utan jämförelse största potentialen. Nedan kommer att diskuteras möjligheter till effektivisering av både konsumtion och produktion av såväl värme som el. Möjligheter till besparingar av elkonsumtion i processer, för drift av strömningsmaskiner etc kommer däremot inte att diskuteras.
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| 69. |
- Berntsson, Thore, 1947
(författare)
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Improved heat pump processes using new refrigerants
- 1981
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Ingår i: Föredrag vid VVS-Mässan i Göteborg, 23-28 oktober. ; 1981
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- During recent years the use of nonazeotropic refrigerantmixtures has been much discussed as a possibility to improvethe COP in various types of heat pumps to small ormoderate additional investment costs. Due to the fact thatnonazeotropic mixtures have gliding temperatures duringthe condensation and the evaporation a heat pump using sucha mixture can often be thermodynamically more fitted tomeet the temperature gradients of the heat sink and theheat source than if a pure refrigerant is used. Earlier research in this field, at least before the seventies, has been emphasized on .refrigeration and air conditioning systems. During recent years, with the growing interest in heat pumps in general, a few experimental investigationsconcerning the use of nonazeotropic mixtures ~n varioustypes of heat pumps have been carried out. Jakobs (1) givesa good literature survey of both theoretical and experimental work in this field made up to 1980 for all types of refrigeration and heat pump applications.In this paper the thermodynamical consequences of using amixture instead of a pure refrigerant will be discussedand some experimental results from investigations at Chaimers and by others will be presented and compared with each other. It will in particular be.'pointed out that the thermodynamical gain with a mixture compared to a pure refrigerant is to a high extent depending on how the comparison is made, i.e. on the assumption of constant outer conditions or constant inner ones in the heat pump itself. In the reference list some papers of interest in this contxt are listed.
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| 70. |
- Berntsson, Thore, 1947
(författare)
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Industriell värmepumpsteknik
- 1992
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Med industriell värmepump menas i denna rapport alla tillämpningar av värmepumptekniken, som använder industriellt sekundärvärme som värmekälla och levererar det producerade värmet till industrins processer eller byggnader och/eller till ett fjärrvärmenät. Jämfört med motsvarande för byggnadsuppvärmning har industriella värmepumpar i många fall följande fördelar:· Höga COP (Coefficient of Performance) beroende på små temperaturlyft och/eller hög temperaturnivå.· Lång årlig drifttid.· Relativt liten investeringskostnad, beroende på stora enheter och små avstånd mellan värmekälla och värmesänka.· Produktionen av spillvärme och behovet av värme uppträder samtidigt i tiden. Trots detta är alltså antalet värmepumpinstallationer i industrin litet jämfört med sådana för byggnadsuppvärmning. Det nämns ofta att huvudorsaken till detta är industrins krav på korta pay-off-tider. Detta är dock inte hela sanningen. Även i situationer där man kan påvisa korta pay-off-tider har värmepumpar hittills installerats endast i liten utsträckning. Andra viktiga orsaker är:· Brist på experiment- och demonstrationsanläggningar i olika typer av industrier.· Osäkerheten hos användarna om driftsäkerheten.· Brist på bra hårdvara för vissa typer av tillämpningar.· Brist på kunskapskombinationen processteknik/värmepumpteknik i industrier och konsultföretag.· Bristande kunskap om processintegration av värmepumpar. Med "industriell" värmepump menas i denna rapport alla tillämpningar av värmepumptekniken, som använder industriellt sekundärvärme som värmekälla och levererar det producerade värmet till industrins processer eller byggnader och/eller till ett fjärrvärmenät.
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