scholarly journals Numerical Analysis and Preliminary Experiment of a Solar Assisted Heat Pump Drying System for Chinese Wolfberry

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4306 ◽  
Author(s):  
Zhongting Hu ◽  
Sheng Zhang ◽  
Wenfeng Chu ◽  
Wei He ◽  
Cairui Yu ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Electric Energy ◽  
Energy Performance ◽  
Operating Conditions ◽  
Pump System ◽  
Heat Pump System ◽  
Electric Energy Consumption ◽  
Drying System ◽  
Heat Pump Drying

The present work investigated a solar assisted heat pump system for drying Chinese wolfberry. The kinetic characteristic was firstly analyzed through a series of lab experiments. It was concluded that the Page model was the most suitable for predicting the heat and mass transfer of the wolfberry. Based on the wolfberry kinetic model, solar collector model and chamber air model, the coupled drying system model was developed. The accuracy of the mathematic model was determined through comparing with the preliminary experimental results. The influence of operating conditions on the thermal and energy performance of the dryer for the different operating mode was discussed. The drying weight of no more than 75 kg may be preferable in the stand-alone solar drying mode, and less than 15 h was needed to be dried. The electric energy consumption in the solar assisted the heat pump drying mode was lower than that in the stand-alone heat pump mode, and it was recommended that about 50 kg of wolfberry to be dried in the solar assisted heat pump system. Compared to the autumn drying, the reduction in the electric energy consumption was around 9.1 kWh during the 11 h summer drying process. The obtained results demonstrated the feasibility of the combined system for drying wolfberry, and also can provide the basic theoretical and experimental data support for the following research.

scholarly journals Comparative Analysis of Heat Pump System with IHX Using R1234yf and R134a

2021 ◽  
Vol 65 (4) ◽  
pp. 363-373
Author(s):  
Róbert Sánta
Keyword(s):  
Heat Pump ◽  
Internal Heat ◽  
Energy Performance ◽  
Operating Conditions ◽  
Pump System ◽  
Heat Pump System ◽  
Internal Heat Exchanger ◽  
Heating Capacity ◽  
Wide Range ◽  
Compressor Power

This research presents an energy performance analysis of the heat pump system with internal heat exchanger (IHX). The mathematical model of the heat pump outlined in this paper has been created by the author, it is steady-state with lumped parameters. The experimental validation of the model has been carried out using R1234yf and R134a as refrigerant. The aim of this work is to compare the energy performance in a wide range of operating conditions of a monitored heat pump system using both refrigerants. Finally, the heating capacity for R1234yf was lower from 0.63 % to 7.54 % compared with R134a, while the compressor power was similar from 0.12 % to 3.51 %. The COP values of R1234yf were lower than those obtained of R134a, ranging from 1.39 % to 4.22 %.

scholarly journals The Role of Emitters, Heat Pump Size, and Building Massive Envelope Elements on the Seasonal Energy Performance of Heat Pump-Based Heating Systems

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5098
Author(s):  
Matteo Dongellini ◽  
Paolo Valdiserri ◽  
Claudia Naldi ◽  
Gian Luca Morini
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Numerical Study ◽  
Thermal Inertia ◽  
Heating System ◽  
Energy Performance ◽  
Building Envelope ◽  
Control Logic ◽  
Pump System ◽  
Heat Pump System

The influence of emitters, heat pump size and building envelope thermal inertia was investigated on the energy consumption of a heat pump-based heating system with a numerical study performed with the dynamic software TRNSYS. An algorithm based on a Thermal Inertia Control Logic (TICL), which can exploit the capability of the building envelope to store thermal energy, has been applied. When the proposed algorithm is employed, the indoor air temperature set-point is increased when the outdoor temperature is larger than the bivalent temperature of the building-heat pump system. Different configurations of the heating system were simulated considering either convective (fan-coil) or radiant (radiant floor) emitters coupled to a variable-speed air-to-water heat pump. Simulations have been carried out considering a reference building derived from the IEA SHC Task 44 and evaluating the influence of the proposed control logic on both the heat pump seasonal energy performance and the internal comfort conditions perceived by the building users. The obtained results highlight how the introduced TICL can guarantee the use of downsized heat pumps, coupled to radiant emitters, with a significant enhancement of the seasonal performance factor up to 10% and a slight improvement of comfort conditions. On the other hand, when convective terminal units are considered the proposed logic is not effective and the overall energy consumption of the system increases up to 15%.

DETERMINING THE PROFITABILITY OF GREENHOUSE ELECTROTECHNOLOGIES: A MODELING APPROACH

HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 249a-249
Author(s):  
Eric A. Lavoie ◽  
Damien de Halleux ◽  
André Gosselin ◽  
Jean-Claude Dufour
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Water System ◽  
Heat Pumps ◽  
Hot Water ◽  
Pump System ◽  
Heat Pump System ◽  
Artificial Lighting ◽  
Hot Air ◽  
Marketable Fruit

The main objective of this research was to produce a simulated model that permitted the evaluation of operating costs of commercial greenhouse tomato growers with respect to heating methods (hot air, hot water, radiant and heat pumps) and the use of artificial lighting for 1991 and 1992. This research showed that the main factors that negatively influence profitability were energy consumption during cold periods and the price of tomatoes during the summer season. The conventional hot water system consumed less energy than the heat pump system and produced marketable fruit yields similar to those from the heat pump system. The hot water system was generally more profitable in regards to energy consumption and productivity. Moreover, investment costs were less; therefore, this system gives best overall financial savings. As for radiant and hot air systems, their overall financial status falls between that of the hot water system and the heat pump. The radiant system proved to be more energy efficient that the hot air system, but the latter produced a higher marketable fruit yield over the 2-year study.

scholarly journals A Comparative Energy and Economic Analysis between a Low Enthalpy Geothermal Design and Gas, Diesel and Biomass Technologies for a HVAC System Installed in an Office Building

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 870 ◽  
Author(s):  
José Villarino ◽  
Alberto Villarino ◽  
I. de Arteaga ◽  
Roberto Quinteros ◽  
Alejandro Alañón
Keyword(s):  
Heat Pump ◽  
Economic Cost ◽  
Operating Conditions ◽  
Office Building ◽  
Geothermal System ◽  
Environmental Aspects ◽  
Pump System ◽  
Heat Pump System ◽  
Heating And Cooling ◽  
Ground Coupled Heat Pump

This paper presents an analysis of economic and energy between a ground-coupled heat pump system and other available technologies, such as natural gas, biomass, and diesel, providing heating, ventilation, and air conditioning to an office building. All the proposed systems are capable of reaching temperatures of 22 °C/25 °C in heating and cooling modes. EnergyPlus software was used to develop a simulation model and carry out the validation process. The first objective of the paper is the validation of the numerical model developed in EnergyPlus with the experimental results collected from the monitored building to evaluate the system in other operating conditions and to compare it with other available technologies. The second aim of the study is the assessment of the position of the low enthalpy geothermal system proposed versus the rest of the systems, from energy, economic, and environmental aspects. In addition, the annual heating and cooling seasonal energy efficiency ratio (COPsys) of the ground-coupled heat pump (GCHP) shown is higher than the others. The economic results determine a period between 6 and 9 years for the proposed GCHP system to have lower economic cost than the rest of the systems. The results obtained determine that the GCHP proposed system can satisfy the thermal demand in heating and cooling conditions, with optimal environmental values and economic viability.

scholarly journals Modeling study of ground source heat pump system based on the dynamic load of underground engineering

2020 ◽  
Vol 182 ◽  
pp. 03004
Author(s):  
Jintian Li ◽  
Yunzhe Ji ◽  
Bo Wang ◽  
Ling Xie
Keyword(s):  
Soil Temperature ◽  
Heat Pump ◽  
Dynamic Load ◽  
Operating Conditions ◽  
Ground Source Heat Pump ◽  
Operating Characteristics ◽  
Underground Engineering ◽  
Pump System ◽  
Heat Pump System ◽  
Ground Source

The load properties of underground engineering have an important influence on operating characteristics of ground source heat pump system. It has important reference value for design and operation management that Simulation analyzing operating conditions of ground source heat pump system under dynamic load conditions. It took an underground engineering as an example for dynamic load calculation in the paper, and simulated operating characteristics of ground source heat pump system under three operating conditions. The calculation results show that the engineering maintenance and management period is conducive to the recovery of soil temperature, and it improves the COP value of the unit. Some measures should be taken to restore soil temperature for long-term continuous operation of underground engineering. The use of heat recovery to make domestic hot water can relieve the problem of soil thermal imbalance to some extent. It is beneficial to improve heat pump unit performance.

Electric torque assist and supercharging of a downsized gasoline engine in a 48V mild hybrid powertrain

2020 ◽  
pp. 095440702096895
Author(s):  
Feihong Xia ◽  
Philip Griefnow ◽  
Florian Tidau ◽  
Moritz Jakoby ◽  
Serge Klein ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Gasoline Engine ◽  
Fuel Efficiency ◽  
Measurement Data ◽  
Electric Energy ◽  
Operating Conditions ◽  
Hybrid Powertrain ◽  
Efficient Operation ◽  
Electric Energy Consumption ◽  
Mild Hybrid

48V systems enable not only mild hybrid functionalities such as recuperation or torque assist by a belt-driven starter generator (BSG), but also electrification of accessories and the engine boosting system. To maximize the powertrain efficiency, a proper layout of the electrified system and an optimized distribution of the electric power during transient operation is essential. In this study, a vehicle co-simulation of a conventional powertrain with a downsized turbocharged gasoline engine is extended by a 48V system with an electric compressor (eC) and a BSG. The control functions of the eC and BSG are based on a state-of-the-art vehicle application and calibrated for transient operating conditions. The engine model, which is built using a one-dimensional crank angle resolved approach in GT-POWER, has been validated with measurement data and is used to predict the interaction between the eC and the engine air path. The investigations using the simulation platform show that the 48V eC and the BSG can significantly improve the fuel effïciency if the electric energy consumption is initially neglected. However, when considering the electric energy consumption within the vehicle co-simulation, efficient operation is particularly depending on driver torque demand, the battery state-of-charge and charging effïciency. Hence, intelligent operating strategies are necessary to take advantage of the better torque response and improve fuel consumption at the same time.

Operational Energy Saving Potential of Thermal Effluent Source Heat Pump System for Greenhouse Heating in Jeju

2017 ◽  
Vol 25 (04) ◽  
pp. 1750030 ◽  
Author(s):  
Min-Hwi Kim ◽  
Dong-Won Lee ◽  
Rin Yun ◽  
Jaehyeok Heo
Keyword(s):  
Power Plant ◽  
Energy Saving ◽  
Heat Pump ◽  
Energy Performance ◽  
Long Distance ◽  
Pump System ◽  
Heat Pump System ◽  
Energy Saving Potential ◽  
Thermal Effluent ◽  
Operational Energy

Massive thermal effluent energy from power plant is mostly released to the sea, and only a little is used for fishing culture and agriculture in South Korea. The thermal effluent from the power plant can be an efficient heat source of the heat pump system to provide heating energy for the greenhouse, but energy loss and pump power by long distance pipeline installation from a power plant to the greenhouse should be considered. In this paper, an operational energy saving potential of a thermal effluent source heat pump system for the greenhouse heating was investigated. For the estimation of thermal load, three cases of greenhouse were categorized, and the thermal performance and operating energy consumption during the heating season were compared with those of a conventional ground source heat pump (GSHP) system. The model for heat pump system was newly derived to estimate the energy performance of the proposed system, and then detailed simulations for each system under three cases of greenhouse were conducted. The results showed that the operational energy of the proposed system can be saved by 17–20% than that of the conventional GSHP system.

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