scholarly journals Direct Contact Liquid-Liquid Heat Exchanger for Solar Heated and Cooled Buildings: Pilot Plant Results

1977 ◽  
Author(s):  
John C. Ward ◽  
Walter M. Loss ◽  
George O.G. Lof
Keyword(s):  
Heat Exchanger ◽  
Pilot Plant ◽  
Direct Contact ◽  
Liquid Heat ◽  
Contact Liquid

scholarly journals Heating performance of a laboratory pilot-plant combining heat exchanger and air scrubber for animal houses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Manuel S. Krommweh ◽  
Wolfgang Büscher
Keyword(s):  
Heat Exchanger ◽  
Air Temperature ◽  
Pilot Plant ◽  
Animal Husbandry ◽  
Operating Costs ◽  
Small Scale ◽  
Heating Performance ◽  
Livestock Buildings ◽  
Reduce Emissions ◽  
Recuperative Heat Exchanger

AbstractExhaust air treatment systems (EATS) are used in animal husbandry to reduce emissions. However, EATS are associated with high acquisition and operating costs. Therefore, a plant technology is being developed that integrates a recuperative heat exchanger into a biological air scrubber. The overall aim is to reduce total costs of livestock buildings with EATS by saving heating costs and to improve animal environment. In this study, a special pilot-plant on a small-scale, using clean exhaust air, was constructed to evaluate the heating performance on laboratory scale. Three assembly situations of the heat exchanger into trickle-bed reactor were part of a trial with two different defined air flow rates. In all three assembly situations, preheating of cold outside air was observed. The heating performance of the assembly situation with the sprayed heat exchanger arranged below showed an average of 4.4 kW at 1800 m3 h−1 (outside air temperature range 0.0–7.9 °C). This is up to 18% higher than the other two experimental setups. The heating performance of the pilot-plant is particularly influenced by the outside air temperature. Further research on the pilot-plant is required to test the system under field conditions.

scholarly journals Numerical Analysis of Liquid–Liquid Heat Pipe Heat Exchanger Based on a Novel Model

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 589
Author(s):  
Qilu Chen ◽  
Yutao Shi ◽  
Zhi Zhuang ◽  
Li Weng ◽  
Chengjun Xu ◽  
...  
Keyword(s):  
Experimental Data ◽  
Heat Exchanger ◽  
Heat Pipe ◽  
Temperature Change ◽  
Current Model ◽  
Change Trend ◽  
Liquid Heat ◽  
Novel Model ◽  
Pipe Heat ◽  
Vapor Temperature

Heat pipe heat exchangers (HPHEXs) are widely used in various industries. In this paper, a novel model of a liquid–liquid heat pipe heat exchanger in a countercurrent manner is established by considering the evaporation and condensation thermal resistances inside the heat pipes (HPs). The discrete method is added to the HPHEX model to determine the thermal resistances of the HPs and the temperature change trend of the heat transfer fluid in the HPHEX. The established model is verified by the HPHEX structure and experimental data in the existing literature and demonstrates numerical results that agree with the experimental data to within a 5% error. With the current model, the investigation compares the effectiveness and minimum vapor temperature of the HPHEX with three types of HP diameters, different mass flow rates, and different H* values. For HPs with a diameter of 36 mm, the effectiveness of each is improved by about 0.018 to 0.029 compared to HPs with a diameter of 28 mm. The results show that the current model can predict the temperature change trend of the HPHEX well; in addition, the effects of different structures on the effectiveness and minimum vapor temperature are obtained, which improve the performance of the HPHEX.

Performance of a Three-Phase, Spray-Column, Direct-Contact Heat Exchanger

1989 ◽  
Vol 111 (1) ◽  
pp. 166-172 ◽  
Author(s):  
T. C¸oban ◽  
R. Boehm
Keyword(s):  
Heat Exchanger ◽  
Direct Contact ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Column Height ◽  
Contact Heat ◽  
Factors Affecting ◽  
Spray Column ◽  
Three Phase ◽  
New Formulation

A numerical model of a three-phase, direct-contact, spray-column heat exchanger has been developed. This model has been used to calculate performance information about this type of device and to compare, where possible, to experiments. General equations are defined for distance up the column using a physically based model for the local heat transfer. This model has been used to investigate a number of characteristics of these devices, such as temperature and holdup distributions through the column. A new formulation is given for a mixed, time-averaged temperature that may be representative of measurements taken with temperature transducers in direct-contact heat exchangers. Little has been given in the literature about quantitative variations of performance as a function of the key independent variables, and information on these aspects is presented here. Although the results presented are for a specific geometry (0.61 m diameter, 3 m active column height, evaporating pentane in 85°C water), the variations shown can give insights generally into the factors affecting performance in these devices. In virtually all cases examined here, extremely good comparisons are shown between predictions and measurements. Conclusions are drawn about the applicability of the model and the important effects demonstrated.

scholarly journals Continuous Hydrothermal Liquefaction of Biomass in a Novel Pilot Plant with Heat Recovery and Hydraulic Oscillation

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2695 ◽  
Author(s):  
Konstantinos Anastasakis ◽  
Patrick Biller ◽  
René Madsen ◽  
Marianne Glasius ◽  
Ib Johannsen
Keyword(s):  
Heat Exchanger ◽  
Sewage Sludge ◽  
Palmitic Acid ◽  
Pilot Plant ◽  
Heat Recovery ◽  
Hydrothermal Liquefaction ◽  
Dry Matter Content ◽  
Oscillation System ◽  
Run Time ◽  
Hydraulic Oscillation

Hydrothermal liquefaction (HTL) is regarded as a promising technology for the production of biofuels from biomass and wastes. As such, there is a drive towards continuous-flow processing systems to aid process scale-up and eventually commercialization. The current study presents results from a novel pilot-scale HTL reactor with a feed capacity of up to 100 L/h and a process volume of approximately 20 L. The pilot plant employs a heat exchanger for heat recovery and a novel hydraulic oscillation system to increase the turbulence in the tubular reactor. The energy grass Miscanthus and the microalgae Spirulina, both representing advanced dedicated energy crops, as well as sewage sludge as high-potential waste stream were selected to assess the reactor performance. Biomass slurries with up to 16 wt% dry matter content were successfully processed. The heat recovery of the heat exchanger is found to increase with reactor run time, reaching 80% within 5–6 h of operation. The hydraulic oscillation system is shown to improve mixing and enhance heat transfer. Bio-crudes with average yields of 26 wt%, 33 wt% and 25 wt% were produced from Miscanthus, Spirulina and sewage sludge, respectively. The yields also appeared to increase with reactor run time. Bio-crude from HTL of Spirulina was mainly composed of palmitic acid, glycerol, heptadecane and linolelaidic acid, while biocrude from sewage sludge contained mainly palmitic acid, oleic acid and stearic acid. In contrast, biocrude from HTL of Miscanthus consisted of a large number of different phenolics. An energetic comparison between the three feedstocks revealed a thermal efficiency of 47%, 47% and 33% and energy return on investment (EROI) of 2.8, 3.3 and 0.5 for HTL of Miscanthus, Spirulina and sewage sludge, respectively.

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