scholarly journals Experimental Assessment of the Thermal Performance of a Heat Pump Dryer System Based on the Variations in Compressor Discharge Pressure on Oregano Drying

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6333
Author(s):  
Arley Salazar-Hincapié ◽  
Alvaro Delgado-Mejía ◽  
Andrés Felipe Romero-Maya ◽  
Eduardo Duque-Grisales
Keyword(s):  
Heat Pump ◽  
Coefficient Of Performance ◽  
Drying Time ◽  
Drying Temperature ◽  
Baseline Case ◽  
Moisture Extraction ◽  
Drying System ◽  
Heat Pump Drying ◽  
Discharge Pressure ◽  
Time And Energy

The current study shows an empirical analysis to establish the effects of the variations in compressor discharge pressure on the drying performance of aromatic herbs, in terms of the coefficient of performance (CoP), moisture content (MC), specific moisture extraction rate (SMER), drying temperature, drying time and energy consumption. In conducting the research, a heat pump drying system was utilized as a mechanism for dehydrating herbs, seeds, and fruits. It was used thanks to its benefits like higher efficiency and its low power consumption. Three levels of discharge pressure were considered, 1380 kPa, 1100 kPa, and 827 kPa, using 1,1,1,2-tetrafluoroethane (R134a) as a refrigerant and oregano leaves as the main product. The findings show that, concerning the same oregano moisture sample, the lower the compressor discharge pressure, the lower drying temperature, also, the higher drying time was obtained. Despite the fact that the CoP decreased with the compressor discharge pressure, in comparison with the baseline case, it remained essentially the same for the other two cases.

Solar-Assisted Heat Pump Drying of Coriander: An Experimental Investigation

2018 ◽  
Vol 26 (04) ◽  
pp. 1850037 ◽  
Author(s):  
Abbas Alishah ◽  
Mohammad Valizadeh Kiamahalleh ◽  
Fereshteh Yousefi ◽  
Anita Emami ◽  
Meisam Valizadeh Kiamahalleh
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Solar Collector ◽  
Coefficient Of Performance ◽  
Air Flow Rate ◽  
Drying Time ◽  
Air Temperatures ◽  
Moisture Extraction ◽  
Heat Pump Drying ◽  
Time And Energy

In this study, the solar-assisted heat pump dryer was designed, manufactured, tested and optimized for drying operations of coriander for its preservation. The heat of drying was mainly provided by a solar collector and a heat pump with two experimental modes of turned on and off. The air temperatures and velocity were identified as the critical drying variables. The responses of the experiments were evaluated in terms of coefficient of performance (COP), energy consumption and the specific moisture extraction rate (SMER). Dehumidification of coriander from the moisture contents of 0.9 to 0.1 kg/kg was considerable. The results demonstrated that utilizing heat pump noticeably decreases the drying time (down to [Formula: see text]25%), energy consumption (down to [Formula: see text]12%) and increases SMER (up to [Formula: see text]20%). The increasing of air flow rate and air temperature significantly led to decreasing the drying time and energy consumption, however, increasing the COP and SMER.

Analysis of a Solar Assisted Heat Pump Dryer With a Storage Tank

Solar Energy ◽  
2006 ◽  
Author(s):  
Yingbai Xie ◽  
Leina Song ◽  
Chuntao Liu
Keyword(s):  
Energy Storage ◽  
Heat Pump ◽  
Storage Tank ◽  
Weather Conditions ◽  
Coefficient Of Performance ◽  
Drying Time ◽  
Energy Inputs ◽  
Drying System ◽  
Typical Summer ◽  
Agriculture Products

In north china, agriculture products may be harvested above safe storage moistures to prevent excessive field losses. A solar-assisted heat pump drying system (SAHP) with an energy storage tank has been proposed to meet the demand in this field. The drying system is designed in such a way that some of the components can be isolated depending on the weather conditions and usage pattern. The performance of the whole system has been modeled and investigated under a typical summer day of the city Baoding, China. Results show that the coefficient of performance (COP) of the SAHP drying system is 5.369, while it is 3.411 without solar energy inputs. With an energy storage tank, the SAHP drying system performs more stable and modulates the mismatch between solar radiation and the energy needed in the night. Other discussions on collector numbers, drying time and drying temperature are also processed, which will be helpful to apply the system in China.

scholarly journals Comparative performance of a solar assisted heat pump dryer with a heat pump dryer for Curcuma

2020 ◽  
Vol 11 (3) ◽  
pp. 1617
Author(s):  
R. Hasibuan ◽  
M Yahya ◽  
H. Fahmi ◽  
Edison Edison
Keyword(s):  
Heat Pump ◽  
Specific Energy Consumption ◽  
Coefficient Of Performance ◽  
Drying Rate ◽  
Comparative Performance ◽  
Drying Time ◽  
Air Mass ◽  
Average Temperature ◽  
Moisture Extraction ◽  
Curcuma Xanthorrhiza

<p>This study evaluated the performances of solar assisted heat pump dryer (SAHPD) and heat pump dryer (HPD) for drying of <em>Curcuma xanthorrhiza Roxb</em>. The HPD and SAHPD reduced mass of <em>Curcuma</em> from 30.70 kg to 7.85 kg needed 10.5 hours and 8 hours with average temperature and relative humidity 49.2oC and 26.5%, and 57.7oC and 19.8%, for SD and SAHPD respectively. The moisture of Curcuma dried from 3.167 db to 0.065 db with an air mass flow rate of 0.121 kg/s. The SAHPD reduced the drying time about 24% compared to HPD. The drying rate and the specific energy consumption were calculated in an average 1.05 kg/h and 1.36kg/h, and 1.17kWh/kg and 2.07kWh/kg for HPD and SAHPD, respectively. The specific moisture extraction rate and the dryer thermal efficiency were calculated in an average 0.931 kg/kWh and 0.521 kg/kWh, and 61.0% and 34.3% for HPD and SAHPD, respectively. Whereas, the pickup efficiency and the coefficient of performance of the heat pump were calculated in an average 57.5% and 59.2%, and 4.03and 4.35 for HPD and SAHPD, respectively. The SAHPD is capable of drying <em>Curcuma</em> quickly because of the high pickup efficiency and high drying rate.</p>

Experimental Performance of a Thermoelectric Heat-Pump Drying System for Drying Herbs

2015 ◽  
Vol 44 (6) ◽  
pp. 2142-2145 ◽  
Author(s):  
K. Wongsim ◽  
J. Jamradloedluk ◽  
C. Lertsatitthanakorn ◽  
S. Siriamornpun ◽  
M. Rungsiyopas ◽  
...  
Keyword(s):  
Heat Pump ◽  
Experimental Performance ◽  
Drying System ◽  
Heat Pump Drying ◽  
Thermoelectric Heat Pump ◽  
Thermoelectric Heat

scholarly journals Drying kinetics and quality aspects during heat pump drying of onion (Allium cepa L.)

2012 ◽  
Vol 1 (2) ◽  
Author(s):  
Nihar Ranjan Sahoo ◽  
Uma Sankar Pal ◽  
Sanjaya Kumar Dash ◽  
M.D. K. Khan
Keyword(s):  
Heat Pump ◽  
Air Temperature ◽  
Colour Change ◽  
Coefficient Of Determination ◽  
Drying Time ◽  
Hot Air ◽  
Thin Layer Drying ◽  
Quality Aspects ◽  
Heat Pump Drying ◽  
Air Dryer

A prototype heat pump dryer has been developed for drying of fruits and vegetables at low temperature and relative humidity to maintain the quality of dried product. Onions, of Nasik red variety were peeled, trimmed and sliced to 2 mm thickness. The onion slices were dried in the heat pump dryer at 35ºC (32 % R.H.), 40ºC (26 % R.H.), 45ºC (19 % R.H.) and 50ºC (15 % R.H.). Samples were also dried in a hot air dryer at 50ºC (52 % R.H.) for comparison. The drying rate increased with increase in drying air temperature, associated with reduced R.H., in the heat pump dryer. Drying took place mainly under the falling rate period. The Page equation, resulting in a higher coefficient of determination and lower root mean square error, better described the thin-layer drying of onion slices than the Henderson and Pabis equation. Heat pump drying took less drying time of 360 min and yielded better quality dried product, with higher retention of ascorbic acid and pyruvic acid and lower colour change, as compared to a hot air dryer at the same drying air temperature of 50ºC.

A Mathematical Model for Thin-Layer Drying of Litchi Pulp

2012 ◽  
Vol 192 ◽  
pp. 51-56
Author(s):  
Zhi Qiang Guan ◽  
Xiu Zhi Wang ◽  
Min Li ◽  
Xiao Qiang Jiang
Keyword(s):  
Experimental Data ◽  
Thin Layer ◽  
Heat Pump ◽  
Moisture Ratio ◽  
Drying Time ◽  
Page Model ◽  
Thin Layer Drying ◽  
Drying Models ◽  
Heat Pump Drying ◽  
Predicted Values

A drying experiment of litchi pulp was done with a self-built heat-pump drying system. A few commonly-used thin-layer drying models for foods were linearized and fitted with the drying experimental data to select a relatively optimal model of depicting the relationship between moisture ratio and drying time of the heat-pump drying of litchi pulp. It was found that the Page model is relatively optimal. The multivariate linear regression approach was employed to solve for the parameters of the Page model based on experimental data and an experimental verification was conducted; the verification results show that the predicted values of the Page model have a good fitness with the measured values and thus the Page model can predict more accurately the moisture ratio and drying rate of litchi pulp in a heat-pump drying process.

scholarly journals Performance Analysis of Heat Pump Dryer with Unit-Room in Cold Climate Regions

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3125 ◽  
Author(s):  
Yuan ◽  
Lin ◽  
Mao ◽  
Li ◽  
Yang ◽  
...  
Keyword(s):  
Heat Pump ◽  
Ambient Air ◽  
Open Loop ◽  
Cold Climate ◽  
Coefficient Of Performance ◽  
Ambient Conditions ◽  
Total Energy Consumption ◽  
Ambient Temperatures ◽  
Moisture Extraction ◽  
Modelling System

This study presents the development and evaluation of a novel partially open-loop heat pump dryer with a unit-room (HPDU). The unit-room was designed to enable the ambient air to be mixed with the return air, thereby reducing the influence of the ambient air on the system performance, while maintaining a high system thermal efficiency. A modelling system for the HPDU was developed and validated based on a real-scale experimental study. By using the modelling system, the system characteristics under different ambient conditions and bypass factors were analyzed. The energy benefit of the proposed HPDU was quantified through a comparative study with a closed-loop heat pump dryer (CHPD). It is evident that a maximal specific moisture extraction rate (SMER) and a minimal total energy consumption (TEC) existed when changing the bypass factor of the HPDU under certain ambient temperatures. Compared to the CHPD, the coefficient of performance (COP) of the HPDU increased by up to 39.56%, presenting a significant energy benefit for the application of HPDU.

scholarly journals Thermodynamic analysis on an instantaneous water heating system of shower wastewater source heat pump

2017 ◽  
Vol 8 (3) ◽  
pp. 404-411 ◽  
Author(s):  
Yuguo Wu ◽  
Yake Jiang ◽  
Bo Gao ◽  
Zhigang Liu ◽  
Jing Liu
Keyword(s):  
Heat Transfer ◽  
Energy Consumption ◽  
Heat Pump ◽  
Water Reuse ◽  
Heating System ◽  
Water Systems ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Heat Transfer Area ◽  
Discharge Pressure

Abstract Water reuse and desalination systems are energy intensive processes, and their increasing use is leading energy consumption within water systems to be an increasingly important issue. Shower wastewater contains large amounts of heat, so there is an opportunity to recover energy from shower water to offset energy consumption elsewhere in water systems. This paper found ways to increase the output of hot water and lower the energy consumption by establishing a thermodynamic model of an instantaneous wastewater source heat pump. The system proved to be very effective, the heating COP (coefficient of performance) can reach 3.3 even in the winter. Under the conditions of limited heat transfer area, reducing the suction pressure of a compressor is a more feasible way to increase the hot water output to meet the needs of users rather than increasing the discharge pressure. Besides, increasing the heat transfer area of the evaporator is a more effective option. When the heat transfer area of evaporator varies from 0.5 to 1.0 square meters, a notable change is that the heating COP increases from 3.283 to 3.936. The heating COP in a system with a recuperator can reach 5.672, almost double that compared to the original systems.

Small Scale Prototype Biomass Drying System for Co-Combustion With Coal

2013 ◽  
Author(s):  
Heather Roberts ◽  
Mitch Favrow ◽  
Jesse Coatney ◽  
David Yoe ◽  
Chenaniah Langness ◽  
...  
Keyword(s):  
Power Plant ◽  
Thermoelectric Power ◽  
Renewable Resources ◽  
Power Plants ◽  
Waste Heat ◽  
Coefficient Of Performance ◽  
Small Scale ◽  
Drying Time ◽  
Thermoelectric Power Plants ◽  
Drying System

Thermoelectric power plants burn thousands of tons of non-renewable resources every day to heat water and create steam, which drives turbines that generate electricity. This causes a significant drain on local resources by diverting water for irrigation and residential usage into the production of energy. Moreover, the use of fossil reserves releases significant amounts of greenhouse and hazardous gases into the atmosphere. As electricity consumption continues to grow and populations rise, there is a need to find other avenues of energy production while conserving water resources. Co-combusting biomass with coal is one potential route that promotes renewable energy while reducing emissions from thermoelectric power plants. In order to move in this direction, there is a need for a low-energy and low-cost system capable of drying materials to a combustion appropriate level in order to replace a significant fraction of the fossil fuel used. Biomass drying is an ancient process often involving the preservation of foods using passive means, which is economically efficient but slow and impractical for large-scale fuel production. This effort, accomplished as an undergraduate capstone design project, instead implements an active drying system for poplar wood using theorized waste heat from the power plant and potentially solar energy. The use of small-scale prototypes demonstrate the principles of the system at a significantly reduced cost while allowing for calculation of mass and energy balances in the analysis of drying time, Coefficient of Performance, and the economics of the process. Experimental tests illustrate the need to distribute air and heat evenly amongst the biomass for consistent drying. Furthermore, the rotation of biomass is critical in order to address the footprint of the system when placing next to an existing thermoelectric power plant. The final design provides a first step towards the refinement and development of a system capable of efficiently returning an amount of biomass large enough to replace non-renewable resources. Finally, an innovative methodology applied to the dryer is discussed that could recover water evaporated from the biomass and utilize it for agricultural purposes or within the power plant thermodynamic cycle.

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