Gas Engine-driven Heat Pump System Research Articles

Demand side management optimization and energy labeling of multi-purpose buildings

A multi-purpose building with different applications such as residential, office, cultural, restaurant, parking, etc. is analyzed in this research. The facilities in many multi-purpose buildings in developing countries are considered having old energy systems with high energy consumption. Application for national energy labeling require optimizing the energy consumption. However, many such buildings in Iran are not awarded the above-mentioned label. The present study aims to assess a multi-purpose building which is not able to get standard energy label with existing situation. To reduce energy consumption in such buildings, solutions such as applying phase-change materials (PCM) in exterior walls, installation of photovoltaics (PV), employing building energy management system (BEMS), and switching the central system to gas engine-driven heat pump (GEHP) were analyzed. The reduction of energy consumption due to PCM, PV, BEMS, and GEHP solutions were 2, 6, 23, and 63%, respectively. The use of PCM, PV, and BEMS failed to enabling the building to receive energy label. Instead, the E category energy label was received only by switching the central heating system to the GEHP system. The payback period for switching the facilities to GEHP system lasted 7.5 years. This method of energy labeling can be used for all of the past multi-purpose Buildings.

Study on performance of a gas engine-driven heat pump system with R410A for heating and domestic hot water applications

Traditional gas engine-driven heat pump (GHP) systems were switched off in the transitional season, and the engine waste heat could no longer be used for producing domestic hot water. Most studies on GHP systems used piston compressors with low efficiency, and the refrigerants used were R134a or R407C. This paper presents an innovative GHP system using open scroll compressors with R410A which can be used throughout the year. The novel GHP system can be switched freely between heating mode-H, which produced heating water combined with domestic hot water, and heating mode-D which only produced domestic hot water. In these two heating modes, the effects of different condenser water outlet temperatures (tw,out1), domestic hot water outlet temperatures (tw,out2), engine speeds (Neng), and total domestic hot water outlet temperatures (tw,out3) on performance of the GHP system for heating and domestic hot water applications were experimentally investigated. The results show that tw,out1 and tw,out3 have greater effect on primary energy ratio (PER), Neng has significantly larger effect on heating capacity and the recovered waste heat, whereas tw,out2 has little effect on the comprehensive performance. The change between heating mode-H and heating mode-D hardly affects the system heating performance. For the experiments, the waste heat recovery rates are between 42.05 % and 61.08 %. The total PER of the GHP system ranges from 1.179 to 1.453 without waste heat recovery, while it ranges from 1.521 to 1.834 when the engine waste heat is recovered. It indicates that the total PER can be significantly improved by recovering the engine waste heat.

Study on performance of a water-source gas engine-driven heat pump system for combined cooling and heating supply

Study on performance of a water-source gas engine-driven heat pump system for combined cooling and heating supply

Investigation of the polygeneration system integrated with gas engine-driven heat pump system and CO2 Brayton cycle for waste heat recovery

A gas engine-driven heat pump system could provide cooling and heating, and fully recover the waste heat. The temperature of the waste heat recovered from the gas engine cylinder jacket and exhaust gas was more than 90℃ and 350℃, respectively. The supercritical CO2 Brayton power cycle is considered a promising primary mover of the combined cooling, heating, and power system to potentially provide higher efficiency. Therefore, a polygeneration system composed of gas engine-driven heat pump system and CO2 Brayton cycle was proposed for cooling, heating, and electricity. Experiments of gas engine-driven heat pump system were conducted and the performances were also investigated in the cooling mode. Meanwhile, the thermodynamic performances of the CO2 Brayton cycle were analyzed. The results indicated that the cooling capacity and waste heat increased with the increase of gas engine speed and decreased with the decrease of evaporator water inlet temperature, the primary energy ratio was 1.032, 0.963, and 0.893 at the gas engine speeds of 1260 r/min, 1510 r/min, and 1820 r/min, respectively, and the increasing range was over 43.5 %. In addition, the maximum net power output of CO2 Brayton cycle was 0.97, 1.68, and 2.14 kW, and the gas engine fuel economy was 12.05, 12.35, and 12.10 kg/kWh at the gas engine speeds 1260 r/min, 1510 r/min, and 1820 r/min, respectively. The decreasing range of gas engine fuel with CO2 Brayton cycle system was 8.6 %, 12.3 %, and 12.5 %, respectively.

Performance of a gas engine-driven heat pump system with R410A for cooling and domestic hot water applications

This research work aimed at systematically evaluating the performance of a gas engine-driven heat pump (GHP) system with R410A for cooling and domestic hot water applications. The changes of cooling capacity (Q˙c), heating capacity of waste heat recovery (Q˙h,dom), total effective utilization energy capacity (Q˙all), gas consumption power (Pgas), primary energy ratio (PER), total primary energy ratio (PERall), coefficient of performance (COP), and the growth rate of PER (RPER) were obtained under the conditions of different evaporator water outlet temperatures tw,out1 (5–18 ℃), engine speeds Neng (1200–2000 r/min), and ambient air temperatures Tamb (30–40 ℃). The results show that the energy efficiency can be significantly improved through waste heat recovery. At low Neng, the effect of engine thermal efficiency (ηeng) is greater than that of COP, and PER shows an increasing trend. However, at high Neng, the effect of ηeng is less than COP, and PER tends to decrease. Among the three effect factors, the Neng and Tamb have significantly larger influence on Q˙h,dom, the tw,out1 and Neng have greater influence on Q˙c, and the Tamb and tw,out1 have greater influence on PER. In the experiments, the values of waste heat recovery rate (Rrec,res) are between 59.84 % and 78.81 %, and the values of RPER are between 31.49 % and 60.58 %. It shows that the GHP system has an excellent waste-heat recovery effect, and the PERall is more than 31.49 % higher than that of the traditional GHP system without waste heat recovery.

Experimental investigation on heating performance of a gas engine-driven heat pump system with R410A

• A novel energy-efficient GHP experimental platform is designed based on scroll compressors with R410A. • The effects of five factors on heating performances of the GHP system are systematically investigated. • The mode-4, which only recovers waste heat using the heating water, can improve the heating performance of the GHP system. • In mode-4, the PER is between 0.981 and 2.155, and the rate of waste heat recovery is between 49.12 % and 77.70 %. In this study, the performance characteristics of a gas engine-driven heat pump (GHP) system for heating applications were experimentally investigated. A novel energy-efficient air-source GHP experimental platform was designed based on scroll compressors with R410A. The changes in heating capacity ( Q h ), gas consumption power ( P gas ), compressor power ( P comp ), primary energy ratio ( PER ), and coefficient of performance ( COP ) were obtained under varying conditions of condenser water flow rate G w (6.10–15.25 m 3 /h), water inlet temperature t w,in (24.0–44.2 ℃), engine speed N eng (1200–2400 r/min), and ambient air temperature T amb (−15–7 ℃). The performances of the four heating modes (mode-1 to mode-4) were compared at an ambient air temperature of −20 ℃. The results showed that t w,in , N eng , and T amb had significant influences on heating performance, whereas G w had a slight impact. Compared with other heating modes, mode-4, wherein the recovered waste heat was only transferred to the heating water, could improve the heating performance of the GHP system. In the mode-4 heating experiments, PER was between 0.981 and 2.155, the rate of waste heat recovery was between 49.12 % and 77.70 %, and the engine thermal efficiency was between 27.02 % and 33.24 %.

Economic analysis of gas heat pump in different building applications:A case study in Shanghai

The application of gas engine driven heat pump (GHP) system can improve the peak valley difference of power and gas system and promote the low-carbon utilization of energy system. The energy consumption of GHP system in different types of buildings and especially the coefficient of performance (COP) under partial load rate needs more analysis. In this paper, according to the local meteorological parameters in Shanghai, the COP operation curve of GHP and electric driven heat pump (EHP) units under partial load rate was analyzed. Combined with the load calculation, the annual energy consumption of GHP and EHP units in different types of buildings, and the influence of energy price on economy of GHP system were analyzed. For office buildings and catering buildings, the energy consumption and operating costs of GHP system were slightly lower than those of EHP system, while for hotel buildings, the annual operating costs of GHP were lower than those of EHP only when the winter gas price was 2.39 yuan/m 3 and the summer gas price was 2.19 yuan/m 3 . Therefore, in order to promote the market competitiveness of gas air conditioning, it is necessary to further refine the gas price or charge standard.

Modelling and Performance Analysis Based on the Core Components of the Gas Engine-Driven Heat Pump System

Modelling and Performance Analysis Based on the Core Components of the Gas Engine-Driven Heat Pump System

Research on waste heat recovery from gas engine for auxiliary heating: An emerging operation strategy to gas engine-driven heat pump

Abstract Gas engine-driven heat pump (GEHP) is attracting increasing interest owing to the high heating efficiency and energy-saving. However, the waste heat from engine is mostly used to directly heat domestic hot water. In this study, a new type of waste heat utilization mode of GEHP was proposed: auxiliary heating. The heating capacity, gas consumption, waste heat recovery and compression ratio of water-source GEHP system with waste heat auxiliary heating mode was studied. In addition, the effects of two utilization modes of engine waste heat domestic hot water (mode Ⅰ) and auxiliary heating (mode Ⅱ) on the thermodynamic parameters were compared. The results indicated that the system efficiency was decrease with engine speed. Even in high speed operation, the primary energy efficiency (PER) of the system was more than 1.55. Under the same range of condenser water inlet temperature, the COP of mode Ⅰ was in the range of 4.71–4.95, and that of mode Ⅱ was in the range of 5.17–5.67. The energy saving and emission saving were also researched. Compared with mode Ⅰ, mode Ⅱ had higher efficiency and less pollution to the environment.

Experimental investigation on cooling performance and optimal superheat of water source gas engine-driven heat pump system

To realize the stability and efficiency of the gas engine-driven heat pump, the cooling performance of system are studied. In this paper, the effects of gas engine and superheat (△Tsh) on system refrigerating capacity, refrigerant mass flow rate, gas consumption, compressor ratio, and system efficiency were researched. Then, taking the speed as the variable parameter, the optimal △Tsh in different working conditions were analyzed. The results showed that high speed is not conducive to the energy-saving operation of the system. In addition, when the △Tsh decreased from 13 °C to 6 °C, the system efficiency increased significantly. When the △Tsh was below 6 °C, the growth rate of efficiency decreased gradually. And there was an optimal △Tsh that made the highest efficiency. The optimal △Tsh increased with the increase of engine speed at the same temperature conditions. When the engine speed were 1200 rpm, 1400 rpm, and 1600 rpm, the optimal △Tsh of the system were 3.5 °C, 3.8 °C and 4.5 °C, respectively. And the corresponding primary energy ratio of system were 2.63, 2.40 and 2.17, respectively.

Experimental Study of a Gas Engine-driven Heat Pump System for Space Heating and Cooling

In this paper, the performance of a gas engine-driven heat pump (GEHP) was experimentally studied for space heating and cooling. An experimental test facility was developed for this purpose. The effect of key parameters on system performance was investigated under both cooling and heating modes. The results showed that as the engine speed increased from 1400 to 2000 rpm, the cooling and heating capacities increased by 23% and 28.5%, respectively while the GEHP system Primary Energy Ratio (PER) decreased by 13.5% and 11.7% in the cooling and heating modes, respectively. The system PER in the cooling mode was found lower than that in the heating mode. This indicated that heat recovery from the engine cylinder and exhaust gas was very important for improving the GEHP system performance. In the heating mode, the ambient temperature and condenser water flow rate had a large effect on the system heating capacity and PER, and insignificant effect on the gas energy input. In the cooling mode, the chilled water inlet temperature showed a large effect on both cooling capacity and gas energy input while the chilled water flow rate had a large effect on cooling capacity and insignificant effect on the gas energy input.

Experimental research on the property of water source gas engine-driven heat pump system with chilled and hot water in summer

The present work aims to explore a new energy supply way for users with chilled and hot water demand in summer. To achieve this goal, a water source gas engine-driven heat pump (WSGHP) system with R134a was developed. The WSGHP system used evaporator to product chilled water, at the same time, made use of condensing heat and engine waste heat to product domestic hot water. The impact of engine speed, evaporator/condenser water inlet temperature on the gas consumption, cooling capacity, heat recovery, and system energy efficiency had been researched in detail. Testing results indicated that the WSGHP system was able to perform stably under various conditions. The primary energy ratio without heat recovery (PER1) of system is from 0.61 to 0.85. However, when the condensing heat and engine waste heat are recovery, its primary energy ratio (PER2) is 2.09–2.34. The cooling capacity, condensing heat and engine waste heat account for 31.5%, 40.0%, and 28.5% of the total capacity of the system, respectively. Therefore, the new energy supply system has great significance to the development of energy-saving and environmental protection.

A Study of Hybrid-Power Gas Engine-Driven Heat Pump Control Strategy Based on Instantaneous Optimization

The control strategy for a coaxial parallel hybrid-power gas engine-driven heat pump system is studied based on instantaneous optimization, aiming at minimizing the equivalent energy consumption. The system includes two main subsystems, drive subsystem and heat pump subsystem. Continuously variable transmission (CVT) is applied to combine the two subsystems for a continuous transmission ratio adjustment. The steady-state models of components of the two subsystems are established, and based on which equivalent energy consumption function is proposed. Meanwhile, a penalty factor is introduced into study of battery to maintain SOC in range of 0.2 to 0.8, where the internal resistance is relatively small. Then computational simulation work is performed on Simulink platform. Result shows that battery SOC runs stable between 0.49∼0.66 and equivalent energy consumption is 10.4% lower than that of system with multi-stage gear ratios.

Experimental study on the gas engine speed control and heating performance of a gas Engine-driven heat pump

ABSTRACT The gas engine-driven heat pump (GEHP) system is an energy saving device for heating, cooling or hot water supply. As the power source of the system, the performance of gas engine speed control directly has a significant impact on the system stability and efficient operation. However, gas engine is typically a nonlinear dynamical system and easily disturbed by the load fluctuation, which increases the difficulty of control of gas engine speed. Therefore, a gas engine speed control strategy is proposed for a GEHP system. Aiming at achieving this objective, a test facility is developed and an engine speed controller is designed according to the characteristics of the gas engine and the GEHP system. Then the engine speed controller is applied to the GEHP system and experiments are performed under different conditions: engine speed setting control and anti-disturbance control. The experimental results show that it costs less than 40 s to make the engine speed steady without overshoot when engine speed setting changes. When the disturbances of superheat change occur, the error (accuracy) of the engine speed is controlled within ± 50 rpm. The engine speed control strategy can not only guarantee the stable operation but also satisfy the capacity adjustment performance of the GEHP system. Finally, performance characteristics of the GEHP are characterized by heating capacity and primary energy ratio (PER). The results indicate that engine speed is an important factor which influences the performance of the GEHP. The heating capacity increases with the increase of engine rotational speed, while PER of the GEHP decreases. In terms of energy saving, the GEHP system should operate at lower engine speed in the case of satisfying the system load.

Experimental investigation of a gas engine-driven heat pump system for cooling and heating operation

The present work aimed at evaluating the performance of a gas engine driven heat pump (GEHP) for cooling and hot water supply. A test prototype working with R134a was built, and the cooling performance with hot water supply were experimented in a range of evaporator water inlet temperature from 12 °C to 22 °C, ambient air temperature from 24.2 °C to 37 °C, and gas engine speeds from 1400 rpm to 2000 rpm. The results show that the effects of evaporator water inlet temperature and gas engine speed on the system performance are more significant than those of ambient air temperature. Average hot water outlet temperatures between 40.7 °C and 61.7 °C are obtained over the considered range of the external operating parameters and this met the temperature demand of domestic water for shaving, residential dish washing, and laundry. Moreover, the primary energy ratio (PER2) of GEHP system is between 1.14 and 1.45 with waste heat recovery.

Thermal modeling and experimental research of a gas engine-driven heat pump in variable condition

In order to analyze the influence of various factors on the system performance of the gas engine-driven heat pump system with waste heat recovery, theoretical model of a gas engine-driven heat pump is conducted in this paper. The thermal modeling of the gas engine-driven heat pump including both the heat pump and the gas engine system was performed and the system performances under different operating parameters were simulated. The results show that the engine speed and the outdoor air temperature affected the system performance significantly. With the engine speed increasing from 1400rpm to 2000rpm, the heating capacity increased by 26.9% while system primary energy ratio (PER) decreased by 17.6% for the air temperature of 10°C. When the outdoor air temperature reduced from 10 to 2°C, the heat capacity reduced by 14.6% but the system PER decreased by 11.8% with the engine speed of 1800rpm. The water inlet temperature act insignificantly on heating capacity, while it had some influence on the system PER. With the water inlet temperature increasing from 38 to 44°C, the system PER decreased by 5.7% and 4.4% for the outdoor air temperature of 10 and 2°C, respectively. The experimental test is also carried out to validate the simulation models. The comparison of modeling results and the experimental measured values for various amounts of the heating capacity, PER, waste heat recovery and the percentage of heat recovery showed 4.8%, 4.6%, 6.7% and 5.6% average difference percentage, which indicated an accepted agreement. From the perspective of energy savings, the gas engine-driven heat pump should be operated with engine speed as low as possible in the case of meeting the heating requirements.

The multi-goal optimal analysis of stand-alone gas engine heat pump system with energy storage (ESGEHP) system

Gas-engine driven heat pump could avoid energy loss in the process of generation, transmission and distribution, and effectively reduce the electric power load at the peak time in summer. In the present study, a novel stand-alone gas engine heat pump system with energy storage is put forward, which combined with the energy storage system and the autonomous power supply system. The annual performance optimization model of the gas engine heat pump system with energy storage system is proposed, which is calculated based on APSO algorithm. The simulation results were well agreed with experimental data, the average difference is 8.9%, 9.63% and 21.7% for the annual primary energy ratio of heating, cooling, transitional season, respectively. Based on the simulation results, the autonomous generating capacity E and the speed of engine n have high effect on the objective function, and the ratio of electricity to heat/cool/domestic hot water should be no greater than 0.1. The annual primary energy ratio of the gas engine heat pump system with energy storage system in heating, cooling and transitional season was increased by 6.11, 19.11% and 34.83% compared with the gas-engine driven heat pump system, respectively. The gas engine heat pump system with energy storage system can be used indifferent climate regions and buildings, which could provide a more stable work mode and higher annual primary energy ratio than the gas-engine driven heat pump system with a little energy loss.

Experimental study on cooling performance and energy saving of gas engine-driven heat pump system with evaporative condenser

The gas engine-driven heat pump (GEHP) is widely utilized to the process of cooling, heating or food drying. Aiming at improving the coefficient of performance (COP), primary energy ratio (PER) and energy saving of GEHP, a GEHP system with evaporative condenser was developed and the cooling performances were experimented over a wide range of ambient air temperature (30–36°C), evaporative condenser air velocity (2.2–3.9m/s) and gas engine speeds (1200–2200rpm). Experimental results showed that the cooling capacity and PER of the GEHP system with evaporative condenser increased as the increasing of evaporative condenser air velocity and decreasing of ambient air temperature. The increasing and decreasing extents of cooling capacity and PER were 12.1%, 4.8% and 8.2%, 9.0%, respectively. However, the gas engine energy consumption and gas engine waste heat decreased with the increasing of evaporative air velocity and decreasing of ambient air temperature. Meanwhile, the cooling capacity, gas engine energy consumption, gas engine waste heat increased with increasing of gas engine speed, and the increase amplitude was 75.64%, 153.2% and 153.3%, respectively. The maximum value of PER of GEHP system with evaporative condenser was 1.55, and the waste heat recovered from gas engine was more than 55% of gas engine energy consumption.The energy saving and emission saving of the GEHP with evaporative condenser were also analyzed, the PER savings of GEHP system with evaporative condenser compared to conventional air-cooled condenser were 28.1%. Furthermore, compared to the GEHP with air-cooled condenser, the primary energy saving and CO2 emissions saving of GHEP with evaporative condenser were 16.3% and 8.8%. The results displayed an excellent energy-saving feature.

Experiments and thermal modeling on hybrid energy supply system of gas engine heat pumps and organic Rankine cycle

This paper presents a hybrid energy supply system, which is composed of two subsystems (gas engine-driven heat pump system (GEHP) and organic Rankine cycle system (ORC)) and three major thermodynamic cycles (the vapor compression refrigeration cycle, the internal combustion gas engine cycle and ORC). In order to convert the low-grade gas engine waste heat into high-grade electricity, the ORC system is built up using R245fa, R152a and R123 as working fluids, and the ORC thermal model is also developed. Meanwhile, experiments of GHEPs in cooling mode are conducted, and several factors which influence the cooling performance are also discussed. The results indicate that the cooling capacity, gas engine energy consumption, gas engine waste heat increase with increasing of gas engine speed and decrease with decreasing of evaporator water inlet temperature. The waste heat recovered from gas engine is more than 55% of gas engine energy consumption. F6urthermore, R123 in ORC system yields the highest thermal and exergy efficiency of 11.84% and 54.24%, respectively. Although, thermal and exergy efficiency of R245fa is 11.42% and 52.25% lower than that of R123, its environmental performance exhibits favorable utilization for ORC using gas engine waste heat as low-grade heat source.

The Performance of Mixture Refrigerant R134a/R152a in a Novel Gas Engine-Driven Heat Pump System

In the present article, a novel gas engine-driven heat pump (GEHP) which could independently provide heating, cooling, and hot water for the buildings with its autonomous power supply system was presented, and the cooling performance characteristics of GEHP using mixture refrigerant R134a/R152a were investigated experimentally. The thermophysical properties and flammability of this proposed mixture refrigerant were analyzed and experimented to approve that it could be used safely in GEHP. The experimental results indicated that the cooling capacity, waste heat recovered from cylinder jacket and exhaust gas, gas engine energy consumption, and compressor power increased with the increase of the gas engine speeds and evaporator water inlet flow rate, but changed in a small range with the increase of the evaporator water inlet temperature except cooling capacity. The generator power remained about 4.90 kW in different operating conditions. Furthermore, the coefficient of performance (COP) and the primary energy ratio (PER) of GEHP also increased with the increase of the evaporator water inlet flow rate and temperature, but decreased with the increase of gas engine speeds. Finally, maximum COP and PER with mixture refrigerant R134a/R152a has been estimated with 8.88 and 1.69 in the aforementioned conditions.