Experimental Study to Investigate the Effect of Backfilling Materials on Thermal Performance of Ground Air Heat Exchanger System

2019 ◽  
pp. 1-36 ◽  
Author(s):  
Kamal Agrawal ◽  
Rohit Misra ◽  
Ghanshyam Das Agrawal
Keyword(s):  
Thermal Properties ◽  
Heat Exchanger ◽  
Air Temperature ◽  
Thermal Performance ◽  
Small Scale ◽  
Outlet Section ◽  
Experimental Setup ◽  
Land Area ◽  
Pipe Length ◽  
Soil Thermal Properties

In ground-air-heat exchanger (GAHE) system, the heat transfer between air and underground soil largely depends on soil thermal properties and therefore, any improvement in soil thermal properties will shorten the pipe length required and the land area needed for its installation. The objective of the present study is to investigate the effect of different backfilling materials (low cost and locally available) on the thermal performance of GAHE system using a small-scale laboratory experimental setup laboratory scale experimental setup. Seven different backfilling materials have been considered for the study and It was observed that after 6 hours of continuous operation, the drop in air temperature was 6.2°C at outlet section of pipe (2.4m away from inlet) for the native soil. However, for sand-bentonite with graphite as a backfilling material (BFM), the drop in air temperature of 6.2°C was obtained at a pipe length of 1.15m only. Therefore, the use of sand-bentonite with graphite as a BFM reduces the pipe length of GAHE system by more than 50%. The study establishes the fact that the length of pipe and land area requirement for GAHE system can be substantially reduced by using thermally enhanced backfilling materials at the close vicinity of GAHE pipes.

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 Optimization of the Performance of Hybrid Solar Biomass Dryer for Drying Maize Using ANSYS Workbench

2020 ◽  
pp. 50-69
Author(s):  
Jackis Aukah ◽  
Mutuku Muvengei ◽  
Hiram Ndiritu ◽  
Calvin Onyango
Keyword(s):  
Heat Exchanger ◽  
Air Temperature ◽  
Small Scale ◽  
Air Velocity ◽  
Hot Air ◽  
Permissible Range ◽  
Feasible Option ◽  
Input Variables ◽  
Drying Chamber ◽  
Ansys Workbench

In this paper ANSYS workbench was used to optimize the performance of hybrid solar biomass dryer for drying shelled maize in order to find the optimal operating input variables when the air temperature within the drying chamber set within the permissible range at reasonably high flow velocity. Hybrid Solar dryer with biomass as a source of fuel for auxiliary heating during absence or low solar insolation is a feasible option for small scale maize farmers [1]. At times high temperatures are induced in this dryer which may result in grain fissures and breakage during milling, thus reducing the grain quality. Optimization results indicate that in order to keep the air temperature within drying chamber to permissible range [2], the air velocity at collector inlet and biomass heat exchanger outlet should be improved to 3 m/s and 2.8 m/s respectively while the capacity of the biomass heat exchanger should also be enhanced to provide hot air at 85°C. It be concluded from the study that HSBD is suitable for drying maize as well as other agricultural products since continuous interrupted drying can be achieved. The capability of the dryer to maintain uniform temperature and air flow within the drying chamber enable high quality dried products within a short duration.

scholarly journals Development and Testing of a 20 kW Moving Packed-Bed Particle-To-sCO2 Heat Exchanger and Test Facility

2021 ◽  
Author(s):  
Kevin J. Albrecht ◽  
Hendrik F. Laubscher ◽  
Matthew D. Carlson ◽  
Clifford K. Ho
Keyword(s):  
Heat Exchanger ◽  
Pressure Drop ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
Packed Bed ◽  
Operating Conditions ◽  
Particle Flow ◽  
Test Facility ◽  
Small Scale ◽  
Flow Loop

Abstract This paper describes the development of a facility for evaluating the performance of small-scale particle-to-sCO2 heat exchangers, which includes an isobaric sCO2 flow loop and an electrically heated particle flow loop. The particle flow loop is capable of delivering up to 60 kW of heat at a temperature of 600 °C and flow rate of 0.4 kg/s. The loop was developed to facilitate long duration off-sun testing of small prototype heat exchangers to produce model validation data at steady-state operating conditions. Lessons learned on instrumentation, control, and system integration from prior testing of larger heat exchangers with solar thermal input were used to guide the design of the test facility. In addition, the development and testing of a novel 20-kWt moving packed-bed particle-to-sCO2 heat exchanger using the integrated flow loops is reported. The prototype heat exchanger implements many novel features for increasing thermal performance and reducing pressure drop which include integral porting of the sCO2 flow, unique bond/braze manufacturing, narrow plate spacing, and pure counter-flow arrangement. The experimental data collected for the prototype heat exchanger was compared to model predictions to verify the sizing, thermal performance, and pressure drop which will be extended to multi-megawatt heat exchanger designs in the future.

scholarly journals Numerical study of a new earth-air heat exchanger configuration designed for Sahara climates

2020 ◽  
Vol 5 (1) ◽  
pp. 22
Author(s):  
Abdessamia Hadjadj
Keyword(s):  
Heat Exchanger ◽  
Thermal Performance ◽  
Arid Regions ◽  
Arid Zone ◽  
Numerical Study ◽  
Airflow Rate ◽  
The Novel ◽  
Populated Area ◽  
Pipe Length ◽  
The Earth

Thermal performance for cooling and heating in the building can be achieved by the novel shape of the earth–air heat exchanger (EAHE). In a heavily populated area such as City, Due to the limited ground space. EAHE systems are rarely used, for most residential andcommercial utilization.This paper presents a numerical investigation of the thermal performance of a spiral-shaped configuration Spiral Earth to Air Heat Exchanger SEAHE intended for the summer cooling inhot and arid regions of Algeria. A parametric analysis of the SEAHE has been performed toinvestigate the effect of diameter, depth, pipe length and of airflow rate on the outlet air in theexchanger. Results show that the specific heat exchange is used to cool in an arid zone (south-east of Algeria). When the ambient temperature varies between 40°C and 45 °C, the coolingtemperature varies between 25°C and 29 °C. Temperature difference inlet and outlet airexchanger 18°C, these values are quite acceptable with for cooling the building.

The Influence of Heat and Moisture Transfer in Soil on the Performance of the Ground Heat Exchanger

2012 ◽  
Vol 594-597 ◽  
pp. 2120-2127
Author(s):  
Guo Min Shen ◽  
Chun Fang Lu ◽  
Yi Wang
Keyword(s):  
Thermal Properties ◽  
Heat Exchanger ◽  
Moisture Content ◽  
Moisture Transfer ◽  
Initial Moisture Content ◽  
Borehole Wall ◽  
Ground Heat Exchanger ◽  
Heat And Moisture Transfer ◽  
Soil Thermal Properties ◽  
Heat And Moisture

In this paper, a numerical heat and moisture transfer model (HMTM) and a pure conduction model (PCM) were established separately for unsaturated soil around the ground heat exchanger (GHE) and were numerically solved by finite volume method. The simulation results indicate that rejecting heat into soil can reduce moisture content in the vicinity of the borehole wall. When the initial moisture content is high, moister transfer has little effect on soil thermal properties. In this case, the results of the HMTM and the PCM are basically identical. On the contrary, when the initial moisture content is low, the thermal effect has significant influence on moisture transfer around the borehole wall, and the soil thermal properties will change correspondingly. In this case, there is a large difference between the results of these two models.

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