- Email: [email protected]
refrigerant enhanced surface tubing
13
With the aid of ring opening metathesis polymerization (ROMP) Bis[(y-(4’cyanobiphenyl)-4-yl)oxy-n-alkyl)norborn-5-ene-2,3-dicarbo~iate was polymerized. A study was carried out into the two disubstituted polynorbornene derivatives both of cis configuration with different lengths of the side-chain. Differential scanning calorimetry (DSC) was used to analyse the effect of thermal history on the assignment of the glass transition event associated with the biaxial orientation of a smectic phase. Calculations were made for the glass transition temperatures. the change of isobaric specific heats at T, and the enthalpies of isotropization.
Thermodynamic considerations on the in-situ formed interface structure observed in Sl-Ti-C-0-fiber/SiOrglass composite Suttor. D. J. Ccvrm. Sock. Jp . 1999. 107. (Jan). 84-88.
00/02141
The preparation of Si-Ti-C-0-fibre/vitreous silica matrix composites, involves the oxidation of the fibres at ambient temperature and subsequent ho-pressing at 1750 C (SO-70 MPa). A silica layer was used to build the matrix on the fibre surfaces formed during initial oxidation. High-resolution transmission electron microscopy revealed the in-siru formation of a graphitic interface with both turbostratic and cellular configuration in addition to TiC crystallites. also precipitated within the silica matrix. The posslbiliry of active oxidation of Sic in the Tyranno fibre yielding gaseous silicon monoxide and solld carbon has been indicated by thermodynamic considerations
00/02142 Thermodynamics computation
of glasses:
combustion
Zeolite-based granular ceramics for improving efficiency of hydrocarbon oils
Sate, K. Jpn, Kokai Tokkyo Koho JP 11 157,922 [99 157.9221 (Cl. C04B351 16), 15 Jun 1999, Appt. 1997/321,585. 21 Nov 1997. 6. (In Japanese) The granular ceramics used for improving combustion efficiency of hydrocarbon oils are fired powder mixtures composed of natural zeolites 40-60, shells 25-35. silica-alumina minerals 12-18. and copper oxide 2-7 wt%. Powder mixtures of natural zeolites (pulverized into an average particle size less than 50 /Im), shells (treated by preliminary firing at 680880” for 10-60 minutes and pulverizing into an average particle size of 50 /im), silica-alumina minerals (treated by preliminary firing at 620-820” for IO-60 minutes and pulverizing into an average particle size 5 50 /Am), and copper oxide are mixed with organic binders, granulated, heated at 500600” for l-6 hours, and fired at 700-1000” for lo-48 hours to produce the ceramics. Hydrocarbon oils, such as gasoline, gas oil and kerosene can be passed through the granular ceramics, which improves combustion efficiency and suppresses the emission of CO and NO,.
13
SPACE HEATING COOLING
00102144 A combined power/cooling Xu. F. _Grrg,. 2000, 25. (3), 233.-246.
AND
cycle
A combined thermal power and cooling cycle is proposed. The proposed cycle combines a Rankine cycle and an absorption refrigeration cycle. It can provide power output as well as refrigeration with power generation as a primary goal. The new cycle uses very high concentration ammonia vapour in the turbine which can be expanded to a very low temperature in the turbine without condensation. This cycle uses an absorption condensation process instead of the conventional condensation process. A parametric analysis of the proposed cycle is presented in this paper. 00/02145
adopting
heahg
and cooling
The possibility of applying binary non-azeotroplc refrigerants in the jet refrigeration cycle are analysed in this paper. For two kinds of working pairs (R30/R142b, R30/Ri24) the thermodynamic cycle performance I\ calculated with the aid of the EOS of PR equation of state. The results are discussed. The theoretical calculations suggest that the quality of refrigeration can be improved if the binary mixtures evaporate just in the low-temperature region.
Boilin characteristics of alternatives to R-502 inside air/refrigerant en a anced surface tubing Sami, S. P. and Desjardins, D. E. hrl. J. Ewrg,~ Re.\.. 3000. 24. ( I ). 27-37
00102147
In this paper, an experimental study on the heat transfer characteristics of two-phase flow boiling of alternative zeotropic refrigerant mixtures to R502, on air/refrigerant horizontal enhanced surface tubing is presented. The new alternatives considered in this study are: R-507. R-404A, R-407B. and R-408A. It was evident from the experimental data that R-502 has the lowest heat transfer rate compared to the other blends in the range investigated. Furthermore, it was also quite evident from these data that R407B has the highest pressure among the blends under investigation. However, at a Reynolds number less than 3.6 x 10J, it appears from the data that R-404A has the lowest pressure drop compared to other refrigerants under investigation.
Comparison studies pulse tube cooler components
00102146
of thermodynamic
losses in
A first principles
Mezard. M. and Parisi, G. Ph!,.r. Rev. fxrr.. 1999. 82. (4). 747.-750. A first principles computation of the equilibrium thermodynamics of simple fragile glasses is proposed. A replica formulation translates this problem into that of a gas of interacting molecules. each molecule being built of 111 atoms. and having a gyration radius (related to the cage size) which vanishes at zero temperature. A small cage expansion is used. valid at low temperatures. which permits one to compute the cage size, the specific heat (which follows the Dulong and Petit law), and the configurational entropy. 00/02143
Space
A criterion for predicting the possible advantage of a suctlonlliquid heat exchanger in refrigerating system
Aprea, C. .4pp/. T/~rr~n. Eng., 1998. 19. (4). 329-336. From a thermodynamic point of view, this paper reports on the possible advantages of adopting a suction/liquid heat exchanger in refrigeration systems. To this purpose, a simplified criterion is presented, this is also validated for many working fluids such as chlorofluorocarbon (CFCs), hydrochlorofluorocarbon (HCFC)s and substitutes on the basis of their thermodynamic properties available in scientific and commercial literature. A graphical form is also used to present the criterion and two examples, referred to as R502 and R32. are provided. 00/02146 Application possibility of binary nonazeotropic refrigerant in jet refrigeration Zhang, Y. Trojl.\. r~trjtlir~ (‘rri~ . 1998. 4. (I). 24-X.
Comparison studies of thermodynamic losses in pulse tube cooler components are presented. The losses in pulse tube coolers include orifice losses and other losses known from similar regenerative coolers. At low cold box temperatures, the orifice loss is relatively small resulting in Stirling cooler performance in a finite parameter range. Improvement areas are identified generically for loss models. After loss summation, a ‘map’ of cooler categories is provided using the shunt model.
00102149 Cooling effect of greenery cover over a building Takakura, T. Encrg~ and B11i1tling.v. 2000. 3 I. (I ). I -6. The cooling effect of various kinds of greenery cover wa\ investigated by both experimental model and computer simulation. Four concrete roof models were constructed and different coverings were arranged for each: bare concrete, soil layer, soil layer with turf. and soil layer with ivy. Temperature profiles, including air temperature in the air space under the roof were measured along with other environmental parameters to calculate the cooling effect. A computer model to simulate the systems and to evaluate cooling load was constructed using the simulation language CSMP. The simulated results matched reasonably well with the measured ones and the cooling effect increased with increase in leaf area per unit roof arca
(LAI). 00102150 Entropy analysis of a flow past a heat-generated
bluff
body Shuja, S. Z. Inr. J. e/ E/WRV Res., 1999. 23, ( 1-i). I 133%I 142. Cooling of a bluff body is a topic of interest for many engmeers and scientists. Forced convection over the bluff body generates flow separation, which in turn affects the heat transfer characteristics and increases the irreversibilities involved in the system. In the present study, flow over a rectangular solid body with constant heat flux is considered. The governing flow and energy equations are solved in two-dimensional \pace numerically using a control volume approach. In order to investigate the effect of the fluid properties on the heating process, three different fluids are taken into account. These are air, ethylene glycol and therminol. To determine the irreversibilities involved in the system, entropy analysis is carried out. It is found that fluid properties have considerable effect on the entropy generation. The entropy generation due to heat transfer well exceeds the entropy generation due to fluid friction. The surface temperature of the solid body highly depends on the cooling fluid employed.
00/02151
Evaluation
of regenerative
phase change
drywalls:
low-energy buildings application
Darkwa, K. f/r!. J. of Owrg~~ Res.. 1999. 23. ( 14). I205 12 17. An integrated phase change drywall system has been analytically evaluated for low-energy huilding applications. The mathematical model indicates that it is possible to attain higher level?, of thermal performance and efficiency with lower values of transfer units (NTU). Even though the model does not take into account rhe variable nature of the thermophysical properties of phase change materials (PCMs). reasonable thermal performance is achievable. Experimental validation is therefore recommended.
00/02152
Finite element and reliability: a method for compound
variables-application on a cracked heating system Mohamed, A. Nlccl. Eng. Des.. 1998. 185. (2-3). I X.5-202. The design of nuclear engineering systems must abide hy certain safety criteria. To predict the behaviour of mechanical systems. the finite element analysis (FEA) is employed for numerical analysis of mechanical problem\. In order to design a system under data variability consideration\. performance functions have to be defined hy the relation between the action effects and the material strengths. Then a certain level of safety should be satisfied with sufficiently high prohahility. This is the subject of the reliability theory. A combination method is used to controlling a FEA
Fuel and Energy Abstracts
July 2000
237
With the aid of ring opening metathesis polymerization (ROMP) Bis[(y-(4’cyanobiphenyl)-4-yl)oxy-n-alkyl)norborn-5-ene-2,3-dicarbo~iate was polymerized. A study was carried out into the two disubstituted polynorbornene derivatives both of cis configuration with different lengths of the side-chain. Differential scanning calorimetry (DSC) was used to analyse the effect of thermal history on the assignment of the glass transition event associated with the biaxial orientation of a smectic phase. Calculations were made for the glass transition temperatures. the change of isobaric specific heats at T, and the enthalpies of isotropization.
Thermodynamic considerations on the in-situ formed interface structure observed in Sl-Ti-C-0-fiber/SiOrglass composite Suttor. D. J. Ccvrm. Sock. Jp . 1999. 107. (Jan). 84-88.
00/02141
The preparation of Si-Ti-C-0-fibre/vitreous silica matrix composites, involves the oxidation of the fibres at ambient temperature and subsequent ho-pressing at 1750 C (SO-70 MPa). A silica layer was used to build the matrix on the fibre surfaces formed during initial oxidation. High-resolution transmission electron microscopy revealed the in-siru formation of a graphitic interface with both turbostratic and cellular configuration in addition to TiC crystallites. also precipitated within the silica matrix. The posslbiliry of active oxidation of Sic in the Tyranno fibre yielding gaseous silicon monoxide and solld carbon has been indicated by thermodynamic considerations
00/02142 Thermodynamics computation
of glasses:
combustion
Zeolite-based granular ceramics for improving efficiency of hydrocarbon oils
Sate, K. Jpn, Kokai Tokkyo Koho JP 11 157,922 [99 157.9221 (Cl. C04B351 16), 15 Jun 1999, Appt. 1997/321,585. 21 Nov 1997. 6. (In Japanese) The granular ceramics used for improving combustion efficiency of hydrocarbon oils are fired powder mixtures composed of natural zeolites 40-60, shells 25-35. silica-alumina minerals 12-18. and copper oxide 2-7 wt%. Powder mixtures of natural zeolites (pulverized into an average particle size less than 50 /Im), shells (treated by preliminary firing at 680880” for 10-60 minutes and pulverizing into an average particle size of 50 /im), silica-alumina minerals (treated by preliminary firing at 620-820” for IO-60 minutes and pulverizing into an average particle size 5 50 /Am), and copper oxide are mixed with organic binders, granulated, heated at 500600” for l-6 hours, and fired at 700-1000” for lo-48 hours to produce the ceramics. Hydrocarbon oils, such as gasoline, gas oil and kerosene can be passed through the granular ceramics, which improves combustion efficiency and suppresses the emission of CO and NO,.
13
SPACE HEATING COOLING
00102144 A combined power/cooling Xu. F. _Grrg,. 2000, 25. (3), 233.-246.
AND
cycle
A combined thermal power and cooling cycle is proposed. The proposed cycle combines a Rankine cycle and an absorption refrigeration cycle. It can provide power output as well as refrigeration with power generation as a primary goal. The new cycle uses very high concentration ammonia vapour in the turbine which can be expanded to a very low temperature in the turbine without condensation. This cycle uses an absorption condensation process instead of the conventional condensation process. A parametric analysis of the proposed cycle is presented in this paper. 00/02145
adopting
heahg
and cooling
The possibility of applying binary non-azeotroplc refrigerants in the jet refrigeration cycle are analysed in this paper. For two kinds of working pairs (R30/R142b, R30/Ri24) the thermodynamic cycle performance I\ calculated with the aid of the EOS of PR equation of state. The results are discussed. The theoretical calculations suggest that the quality of refrigeration can be improved if the binary mixtures evaporate just in the low-temperature region.
Boilin characteristics of alternatives to R-502 inside air/refrigerant en a anced surface tubing Sami, S. P. and Desjardins, D. E. hrl. J. Ewrg,~ Re.\.. 3000. 24. ( I ). 27-37
00102147
In this paper, an experimental study on the heat transfer characteristics of two-phase flow boiling of alternative zeotropic refrigerant mixtures to R502, on air/refrigerant horizontal enhanced surface tubing is presented. The new alternatives considered in this study are: R-507. R-404A, R-407B. and R-408A. It was evident from the experimental data that R-502 has the lowest heat transfer rate compared to the other blends in the range investigated. Furthermore, it was also quite evident from these data that R407B has the highest pressure among the blends under investigation. However, at a Reynolds number less than 3.6 x 10J, it appears from the data that R-404A has the lowest pressure drop compared to other refrigerants under investigation.
Comparison studies pulse tube cooler components
00102146
of thermodynamic
losses in
A first principles
Mezard. M. and Parisi, G. Ph!,.r. Rev. fxrr.. 1999. 82. (4). 747.-750. A first principles computation of the equilibrium thermodynamics of simple fragile glasses is proposed. A replica formulation translates this problem into that of a gas of interacting molecules. each molecule being built of 111 atoms. and having a gyration radius (related to the cage size) which vanishes at zero temperature. A small cage expansion is used. valid at low temperatures. which permits one to compute the cage size, the specific heat (which follows the Dulong and Petit law), and the configurational entropy. 00/02143
Space
A criterion for predicting the possible advantage of a suctlonlliquid heat exchanger in refrigerating system
Aprea, C. .4pp/. T/~rr~n. Eng., 1998. 19. (4). 329-336. From a thermodynamic point of view, this paper reports on the possible advantages of adopting a suction/liquid heat exchanger in refrigeration systems. To this purpose, a simplified criterion is presented, this is also validated for many working fluids such as chlorofluorocarbon (CFCs), hydrochlorofluorocarbon (HCFC)s and substitutes on the basis of their thermodynamic properties available in scientific and commercial literature. A graphical form is also used to present the criterion and two examples, referred to as R502 and R32. are provided. 00/02146 Application possibility of binary nonazeotropic refrigerant in jet refrigeration Zhang, Y. Trojl.\. r~trjtlir~ (‘rri~ . 1998. 4. (I). 24-X.
Comparison studies of thermodynamic losses in pulse tube cooler components are presented. The losses in pulse tube coolers include orifice losses and other losses known from similar regenerative coolers. At low cold box temperatures, the orifice loss is relatively small resulting in Stirling cooler performance in a finite parameter range. Improvement areas are identified generically for loss models. After loss summation, a ‘map’ of cooler categories is provided using the shunt model.
00102149 Cooling effect of greenery cover over a building Takakura, T. Encrg~ and B11i1tling.v. 2000. 3 I. (I ). I -6. The cooling effect of various kinds of greenery cover wa\ investigated by both experimental model and computer simulation. Four concrete roof models were constructed and different coverings were arranged for each: bare concrete, soil layer, soil layer with turf. and soil layer with ivy. Temperature profiles, including air temperature in the air space under the roof were measured along with other environmental parameters to calculate the cooling effect. A computer model to simulate the systems and to evaluate cooling load was constructed using the simulation language CSMP. The simulated results matched reasonably well with the measured ones and the cooling effect increased with increase in leaf area per unit roof arca
(LAI). 00102150 Entropy analysis of a flow past a heat-generated
bluff
body Shuja, S. Z. Inr. J. e/ E/WRV Res., 1999. 23, ( 1-i). I 133%I 142. Cooling of a bluff body is a topic of interest for many engmeers and scientists. Forced convection over the bluff body generates flow separation, which in turn affects the heat transfer characteristics and increases the irreversibilities involved in the system. In the present study, flow over a rectangular solid body with constant heat flux is considered. The governing flow and energy equations are solved in two-dimensional \pace numerically using a control volume approach. In order to investigate the effect of the fluid properties on the heating process, three different fluids are taken into account. These are air, ethylene glycol and therminol. To determine the irreversibilities involved in the system, entropy analysis is carried out. It is found that fluid properties have considerable effect on the entropy generation. The entropy generation due to heat transfer well exceeds the entropy generation due to fluid friction. The surface temperature of the solid body highly depends on the cooling fluid employed.
00/02151
Evaluation
of regenerative
phase change
drywalls:
low-energy buildings application
Darkwa, K. f/r!. J. of Owrg~~ Res.. 1999. 23. ( 14). I205 12 17. An integrated phase change drywall system has been analytically evaluated for low-energy huilding applications. The mathematical model indicates that it is possible to attain higher level?, of thermal performance and efficiency with lower values of transfer units (NTU). Even though the model does not take into account rhe variable nature of the thermophysical properties of phase change materials (PCMs). reasonable thermal performance is achievable. Experimental validation is therefore recommended.
00/02152
Finite element and reliability: a method for compound
variables-application on a cracked heating system Mohamed, A. Nlccl. Eng. Des.. 1998. 185. (2-3). I X.5-202. The design of nuclear engineering systems must abide hy certain safety criteria. To predict the behaviour of mechanical systems. the finite element analysis (FEA) is employed for numerical analysis of mechanical problem\. In order to design a system under data variability consideration\. performance functions have to be defined hy the relation between the action effects and the material strengths. Then a certain level of safety should be satisfied with sufficiently high prohahility. This is the subject of the reliability theory. A combination method is used to controlling a FEA
Fuel and Energy Abstracts
July 2000
237