scholarly journals Optimisation of Control Input Allocation Maps for Electric Vehicle Heat Pump-based Cabin Heating Systems

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5131
Author(s):  
Ivan Cvok ◽  
Igor Ratković ◽  
Joško Deur
Keyword(s):  
Electric Vehicle ◽  
Heat Pump ◽  
Air Temperature ◽  
Control Strategy ◽  
Air Conditioning ◽  
Control Input ◽  
Hvac System ◽  
System Efficiency ◽  
Pump Mode ◽  
Superheat Temperature

The heating, ventilation and air conditioning (HVAC) system negatively affects the electric vehicle (EV) driving range, especially under cold ambient conditions. Modern HVAC systems based on the vapour-compression cycle can be rearranged to operate in the heat pump mode to improve the overall system efficiency compared to conventional electrical/resistive heaters. Since such an HVAC system is typically equipped with multiple actuators (compressor, pumps, fans, valves), with the majority of them being controlled in open loop, an optimisation-based control input allocation is necessary to achieve the highest efficiency. This paper presents a genetic algorithm optimisation-based HVAC control input allocation method, which utilises a multi-physical HVAC system model implemented in Dymola/Modelica. The considered control inputs include the cabin inlet air temperature reference, blower and radiator fan air mass flows and secondary coolant loop pumps’ speeds. The optimal allocation is subject to specified, target cabin air temperatures and heating power. Additional constraints include actuator hardware limits and safety functions, such as maintaining the superheat temperature at its reference level. The optimisation objective is to maximise the system efficiency defined by the coefficient of performance (COP). The optimised allocation maps are fitted by proper mathematical functions to facilitate the control strategy implementation and calibration. The overall control strategy consists of superimposed cabin air temperature controller that commands heating power, control input allocation functions, and low-level controllers that ensure cabin inlet air and superheat temperature regulation. The control system performance is verified through Dymola simulations for the heat pump mode in a heat-up scenario. Control input allocation map optimisation results are presented for air-conditioning (A/C) mode, as well.

scholarly journals Heat pump air conditioning system for pure electric vehicle at ultra-low temperature

2014 ◽  
Vol 18 (5) ◽  
pp. 1667-1672 ◽  
Author(s):  
Hai-Jun Li ◽  
Guang-Hui Zhou ◽  
An-Gui Li ◽  
Xu-Ge Li ◽  
Ya-Nan Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Electric Vehicle ◽  
Heat Pump ◽  
Air Conditioning ◽  
Heating System ◽  
Experimental Results ◽  
Air Conditioning System ◽  
Discharge Temperature ◽  
Heating Capacity ◽  
Environment Temperature

When the ordinary heat pump air conditioning system of a pure electric vehicle runs at ultra-low temperature, the discharge temperature of compressor will be too high and the heating capacity of the system will decay seriously, it will lead to inactivity of the heating system. In order to solve this problem, a modification is put forward, and an experiment is also designed. The experimental results show that in the same conditions, this new heating system increases more than 20% of the heating capacity; when the outside environment temperature is negative 20 degrees, the discharge temperature of compressor is below 60 degrees.

scholarly journals Optimal Control Strategy for Variable Air Volume Air-Conditioning Systems Using Genetic Algorithms

2019 ◽  
Vol 11 (18) ◽  
pp. 5122 ◽  
Author(s):  
Nam-Chul Seong ◽  
Jee-Heon Kim ◽  
Wonchang Choi
Keyword(s):  
Optimal Control ◽  
Genetic Algorithms ◽  
Control Strategy ◽  
Air Conditioning ◽  
Static Pressure ◽  
Hvac System ◽  
Total Energy Consumption ◽  
Optimal Control Strategy ◽  
Variable Air Volume ◽  
Air Volume

This study is aimed at developing a real-time optimal control strategy for variable air volume (VAV) air-conditioning in a heating, ventilation, and air-conditioning (HVAC) system using genetic algorithms and a simulated large-scale office building. The two selected control variables are the settings for the supply air temperature and the duct static pressure to provide optimal control for the VAV air-conditioning system. Genetic algorithms were employed to calculate the optimal control settings for each control variable. The proposed optimal control conditions were evaluated according to the total energy consumption of the HVAC system based on its component parts (fan, chiller, and cold-water pump). The results confirm that the supply air temperature and duct static pressure change according to the cooling load of the simulated building. Using the proposed optimal control variables, the total energy consumption of the building was reduced up to 5.72% compared to under ‘normal’ settings and conditions.

scholarly journals Heating, Ventilation, and Air Conditioning System Optimization Control Strategy Involving Fan Coil Unit Temperature Control

2019 ◽  
Vol 9 (11) ◽  
pp. 2391 ◽  
Author(s):  
Chang-Ming Lin ◽  
Hsin-Yu Liu ◽  
Ko-Ying Tseng ◽  
Sheng-Fuu Lin
Keyword(s):  
Genetic Algorithm ◽  
Energy Conservation ◽  
Temperature Control ◽  
Control Strategy ◽  
Air Conditioning ◽  
Minimum Energy ◽  
System Optimization ◽  
Hvac System ◽  
Minimum Energy Consumption ◽  
Optimization Control

The objective of this study was to develop a heating, ventilation, and air conditioning (HVAC) system optimization control strategy involving fan coil unit (FCU) temperature control for energy conservation in chilled water systems to enhance the operating efficiency of HVAC systems. The proposed control strategy involves three techniques, which are described as follows. The first technique is an algorithm for dynamic FCU temperature setting, which enables the FCU temperature to be set in accordance with changes in the outdoor temperature to satisfy the indoor thermal comfort for occupants. The second technique is an approach for determining the indoor cold air demand, which collects the set FCU temperature and converts it to the refrigeration ton required for the chilled water system; this serves as the control target for ensuring optimal HVAC operation. The third technique is a genetic algorithm for calculating the minimum energy consumption for an HVAC system. The genetic algorithm determines the pump operating frequency associated with minimum energy consumption per refrigeration ton to control energy conservation. To demonstrate the effectiveness of the proposed HVAC system optimization control strategy combining FCU temperature control, this study conducted a field experiment. The results revealed that the proposed strategy enabled an HVAC system to achieve 39.71% energy conservation compared with an HVAC system operating at full load.

Snow Utilization as Cold Heat Source - Advantages and Features

2019 ◽  
Vol 889 ◽  
pp. 549-556
Author(s):  
Seiji Kamimura ◽  
Yoshiomi Ito
Keyword(s):  
Heat Source ◽  
Heat Pump ◽  
Air Temperature ◽  
Temperature Control ◽  
Annual Cost ◽  
Air Conditioning ◽  
Cost Effective ◽  
Shiitake Mushroom ◽  
Pump Unit ◽  
Heat Pump Unit

In the summer of 2014, the air-conditioning performance of four different snow-utilizing facilities in Niigata and Nagano Prefectures in Japan were evaluated. Systems with a snow storeroom, a rice depot and spa resort, showed the advantages of stable and flexible air temperature control with high deodorizing and dedusting effects. The investment will be earned back in less than 10 years. The system with a snow mound, shiitake mushroom greenhouses, showed that the annual cost is cheaper than that of the heat pump unit. A highway lavatory with daily snow delivery was not cost effective.

An Investigation of Energy Consumption, Solar Fraction and Hybrid Photovoltaic–Thermal Solar Dryer Parameters in Drying of Chamomile Flower

2014 ◽  
Vol 10 (4) ◽  
pp. 697-711 ◽  
Author(s):  
Saeid Minaei ◽  
Ali Motevali ◽  
Barat Ghobadian ◽  
Ahmad Banakar ◽  
Seyed Hashem Samadi
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Air Temperature ◽  
Coefficient Of Performance ◽  
Pump Mode ◽  
Energy Fraction ◽  
Drying Time ◽  
Solar Dryer ◽  
Drying Behavior ◽  
Chamomile Flower

Abstract In this research, drying of a medicinal plant (chamomile) in a hybrid photovoltaic–thermal solar dryer with and without heat pump was investigated. The experiments were performed at three air speeds (0.5, 1, and 1.5 m/s), three levels of air temperature (40, 50, and 60°C), with and without using a heat pump. Results of analysis indicated that adding a heat pump to the photovoltaic solar dryer decreases drying time, energy consumption, and required specific energy. Solar energy fraction increased with decreasing air temperature and velocity. Analysis of the dryer-related parameters showed that the maximum and minimum thermal efficiencies were 33.8 and 16.4%, respectively, both in the no-heat-pump mode while with the heat pump, its maximum and minimum values were 38.4 and 19.7%, respectively. Moreover, the highest and lowest electrical efficiencies for the no-heat-pump mode were 13.4 and 9.1%, respectively; while using the heat pump, its maximum and minimum values were 14.1 and 10.4%, respectively. Results of analyzing the dryer’s coefficient of performance for drying chamomile showed that the highest and lowest coefficients of performance were 3.41 and 1.82, respectively. Eleven mathematical models were tested, and Page’s model was selected as the best for describing the drying behavior of chamomile flower.

scholarly journals Climate Compensation and Indoor Temperature Optimal Measuring Point Energy Saving Control in VAV Air-Conditioning System

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4398 ◽  
Author(s):  
Xiuying Yan ◽  
Cong Liu ◽  
Meili Li ◽  
Ating Hou ◽  
Kaixing Fan ◽  
...  
Keyword(s):  
Energy Saving ◽  
Air Temperature ◽  
Control Strategy ◽  
Air Conditioning ◽  
Compensation Scheme ◽  
Indoor Temperature ◽  
Air Conditioning System ◽  
Measuring Point ◽  
Temperature Measuring ◽  
Environment Control

Temperature measuring point is the key to room environment control. Temperature measuring points and climate changes are directly related to the room control effect. It is of great theoretical and practical significance to study the temperature measuring points and control strategy based on climate compensation. In this study, first, the climate compensation concept in a heating system was introduced into a variable air volume (VAV) air-conditioning system. The heating load was modeled as a function of supply air temperature by analyzing the heat exchange. Based on each control link of subsystems, a climate compensation scheme is proposed to determine the optimal set-point of the supply air temperature. At the same time, a layout of multiple temperature measuring points of an air-conditioned room was studied. Furthermore, the optimal indoor temperature measuring point was determined using an adaptive weighted fusion method. Finally, simulation results show that the proposed method has better control effects on indoor temperature adjustment compared with the traditional method. The optimal supply air temperature in summer and winter was determined according to the proposed climate compensation scheme, and the supply air temperature was controlled using an improved single-neuron adaptive control strategy. Experimental results show that the maximum energy saving can reach up to 35.5% in winter and 6.1% in summer.

scholarly journals Automated method of calculation of parameters for non-traditional heating technologies and conditioning of buildings

2021 ◽  
pp. 40-47
Author(s):  
Illia Olishevskyi ◽  
Hennadiy Olishevskyi
Keyword(s):  
Water Supply ◽  
Heat Pump ◽  
Air Temperature ◽  
Air Conditioning ◽  
Warm Period ◽  
Hot Water ◽  
Heat Accumulator ◽  
Automated Method ◽  
Hot Water Supply ◽  
Conventional Fuel

Purpose. Develop an automated method for calculating parameters for heat pump systems for heating, air conditioning and hot water supply, designed for use in domestic conditions with non-standard heat transfer flows. Methodology. Mathematical modeling of thermodynamic processes occurring in heating, air conditioning and hot water supply systems. Findings. The automated method of calculating the parameters of non-traditional technology, which uses standard heat pump equipment of the water heating system for the cooling mode of the air in the warm period of the year, and the discharge of heat dissipated into the ground, was substantiated and developed; and for the needs of hot water supply heat pump air-liquid, acting as a high-speed water heater. The estimation of technologies of the thermal energy utilization in buildings developed earlier by authors is executed. The first technology involved the use of a heat pump and heat accumulator scheme in the cold season, and halved the consumption of conventional fuel compared to a gas column for hot water at the same facility. The second technology involved heat recovery with the help of a heat accumulator in a complex system of air conditioning and hot water supply in the warm period, which saves from 74 to 82% of conventional fuel compared to the scheme with boiler and air conditioner without heat accumulator. Critical conclusions were drawn about the need to use additional dimensional equipment for these technologies and the excess amount of hot water received. Possibilities of realization of such scheme were analyzed. Analytically substantiated recommendations on the design (ribbing of heat exchange surfaces) of heating devices and parameters of their operating modes in the cold and warm periods of the year were given. The condition of invariance of heat exchange areas of heating devices and basic water consumption in the heating system was fulfilled. The need to regulate the air conditioning regime by changing the water flow in the system to maintain a constant indoor air temperature with fluctuations in outdoor air temperature was substantiated. Originality.  For the first time, attention is paid to the study of non-traditional methods of using heat pump heating for heating, air conditioning and hot water supply of residential premises. The automated method for determining rational parameters for these technologies was developed. Practical value. The automated method of forming the control dependence of the mass flow of water in the system on the outside air temperature on the condition of constancy of the set comfortable indoor air temperature was developed. The use of air-liquid heat pump for hot water supply in the warm period was analyzed, a high energy conversion factor was noted (14 ... 22). The savings of conventional fuel from the application of the considered technology from 13% to 18% in comparison with the technology using a heat accumulator were substantiated.

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