Transient System Simulation Software Research Articles

Performance Evaluation of Radiator and Radiant Floor Heating Systems for an Office Room Connected to a Ground-Coupled Heat Pump

A ground-coupled heat pump (GCHP) system used to provide the space heating for an office room is a renewable, high performance technology. This paper discusses vapour compression-based HP systems, briefly describing the thermodynamic cycle calculations, as well as the coefficient of performance (COP) and CO2 emissions of a HP with an electro-compressor and compares different heating systems in terms of energy consumption, thermal comfort and environmental impact. It is focused on an experimental study performed to test the energy efficiency of the radiator or radiant floor heating system for an office room connected to a GCHP. The main performance parameters (COP and CO2 emissions) are obtained for one month of operation of the GCHP system, and a comparative analysis of these parameters is presented. Additionally, two numerical simulation models of useful thermal energy and the system COP in heating mode are developed using the Transient Systems Simulation (TRNSYS) software. Finally, the simulations obtained from TRNSYS software are analysed and compared to the experimental data, showing good agreement and thus validating the simulation models.

Performance Assessment of a Ground-coupled Heat Pump for an Office Room Heating using Radiator or Radiant Floor Heating Systems

The ground-coupled heat pump (GCHP) system used to provide space heating for an office room is a renewable technology with a high performance. The experimental measurements are used to test the performance of a GCHP system integrated with the radiator or radiant floor heating system for an office room. A comparative analysis of the main performance parameters (energy efficiency and CO2 emissions) is performed for the two heating systems. Additionally, two numerical simulation models of useful thermal energy and the system coefficient of performance (COPsys) in heating mode are developed using the TRNSYS (Transient Systems Simulation) software. Finally, the simulations obtained using TRNSYS software are analysed and compared to the experimental data, resulting in good agreement and thus the simulation models are validated.

Performance Evaluation of Photovoltaic String with Compound Parabolic Concentrator

 Abstract—Photovoltaic (PV) system is used to directly converting the solar energy into the electrical energy. Compound Parabolic Concentrator (CPC) is a non-imaging concentrator which is considered in this study for reducing the cost of electrical energy. Two configurations are numerically studied namely one with simple typical flat PV string and the other PV string with CPC. The truncated CPC with concentration ratio of 2.3 and an acceptance angle of 41.75° is considered in the analysis of PV string with CPC (PV-CPC). Transient System Simulation Software (TRNSYS) is used for the evaluation of PV cell performance with and without CPC. The mathematical model for PV and PV-CPC is developed for the performance estimation of thermal and electrical characteristic of the system. Engineering Equation Solver (EES) code is written to solve the mathematical model and is linked with TRNSYS for simulation. The simulation is carried out for the average day of the months of June and December for Riyadh city. Results indicated that the use of the CPC increases the absorbed energy and electrical power output of PV system. The electrical power of PV string increases almost 35% when CPC is used with PV compared to simple typical flat PV string.

Integrated control of the cooling system and surface openings using the artificial neural networks

This study aimed at suggesting an indoor temperature control method that can provide a comfortable thermal environment through the integrated control of the cooling system and the surface openings. Four control logic were developed, employing different application levels of rules and artificial neural network models. Rule-based control methods represented the conventional approach while ANN-based methods were applied for the predictive and adaptive controls. Comparative performance tests for the conventional- and ANN-based methods were numerically conducted for the double-skin-facade building, using the MATLAB (Matrix Laboratory) and TRNSYS (Transient Systems Simulation) software, after proving the validity by comparing the simulation and field measurement results.Analysis revealed that the ANN-based controls of the cooling system and surface openings improved the indoor temperature conditions with increased comfortable temperature periods and decreased standard deviation of the indoor temperature from the center of the comfortable range. In addition, the proposed ANN-based logic effectively reduced the number of operating condition changes of the cooling system and surface openings, which can prevent system failure. The ANN-based logic, however, did not show superiority in energy efficiency over the conventional logic. Instead, they have increased the amount of heat removal by the cooling system. From the analysis, it can be concluded that the ANN-based temperature control logic was able to keep the indoor temperature more comfortably and stably within the comfortable range due to its predictive and adaptive features.

Performance of an experimental ground-coupled heat pump system for heating, cooling and domestic hot-water operation

The ground-coupled heat pump (GCHP) system is a type of renewable energy technology providing space heating and cooling as well as domestic hot water. However, experimental studies on GCHP systems are still insufficient. This paper first presents an energy-operational optimisation device for a GCHP system involving insertion of a buffer tank between the heat pump unit and fan coil units and consumer supply using quantitative adjustment with a variable speed circulating pump. Then, the experimental measurements are used to test the performance of the GCHP system in different operating modes. The main performance parameters (energy efficiency and CO2 emissions) are obtained for one month of operation using both classical and optimised adjustment of the GCHP system, and a comparative analysis of these performances is performed. In addition, using TRNSYS (Transient Systems Simulation) software, two simulation models of thermal energy consumption in heating, cooling and domestic hot-water operation are developed. Finally, the simulations obtained using TRNSYS are analysed and compared to experimental data, resulting in good agreement and thus the simulation models are validated.

Improving the Energy Performance of HVAC Systems in Operating Theatres by Using Heat Recovery Devices

Heating, ventilation and air conditioning (HVAC) systems in operating theaters use fully fresh air, and return air is not allowed to be mixed with the fresh air. Therefore, HVAC systems in operating theaters are inherently energy-inefficient. In this research, the impact of heat pipe heat exchanger (HPHX) as a heat recovery device on the performance of an existing HVAC system of an operating theater was examined. The existing HVAC system, Plant A, was redesigned by the added HPHX as Plant B and C and the most suitable design in terms of energy consumption level and provided air conditions was recommended for the system. A transient system simulation software (TRNSYS) was used for the simulation of the systems for a yearly operation of 8760 hours. Based on the results, the application of HPHX, Plant C configuration, could decrease the energy demand of the system and it is recommended to be implemented in the existing HVAC system. Moreover, it was shown that the HPHX integrated system improves the room and supply duct air conditions.

Simulation of cogeneration within the concept of smart energy networks

Recently tremendous research effort has been made to cope with the challenges in providing a sustainable energy solution for achieving economic and environmental goals. The concept of smart energy networks (SEN) goes beyond the electricity-based smart grid (SG) environment. The availability of new technologies for utilizing renewables such as solar, wind, geothermal and biomass and possibility of integrating natural gas and heating/cooling pipelines into the electricity grid network have provided a base for reducing the carbon footprint of fossil fuels and to produce a better energy security in a SEN environment. Especially, cogeneration systems in SEN can provide a promising solution for effectively supplying energy from a variety of combine heat and power generators to district consumers in an urban environment. In this study, a community-scale energy network is modeled and simulated using TRNSYS (Transient System Simulation Software) to investigate the impacts of the selected cogeneration systems on real-time critical parameters of SEN. The simulation results show that, through analyzing the key factors, the cogeneration model can be technically and economically feasible in SEN environment. The model follows effectively the heat-to-power ratios of the individual components and meets the energy demand with less excess electricity supply. The model describes a high renewable contribution ratio of 23.5% and gives a high overall efficiency which is about 12.6% higher than that of the separate heat and power generation system, resulting in a low emission level which is 34.2% lower than that of the separate heat and power generation.

The application of heat pipe heat exchangers to improve the air quality and reduce the energy consumption of the air conditioning system in a hospital ward—A full year model simulation

Research was conducted to study the effect of heat pipe heat exchangers on the existing air conditioning system of a hospital ward located in Malaysia, a tropical region. The present research employs the transient system simulation software (TRNSYS) to study the hour-by-hour performance of the system in terms of supply duct air and indoor air conditions in the ward space. Fieldwork study showed that the existing air conditioning system operating in the Orthopaedic Ward, University of Malaya, Malaysia is not capable of providing the desired supply duct air and indoor air to the space. Therefore, the possibility of improving the air conditioning system by adding heat pipe heat exchangers was investigated. The impact on energy consumption, power savings, supply duct air and indoor air with heat pipe heat exchangers incorporated in the air conditioning system were simulated and the results were compared with the existing system. Based on the present research, the system with the added eight-row heat pipe heat exchangers is recommended to provide convenient and healthy air into the ward space according to the ASHRAE recommendations. Moreover, it was found that by applying the new design, a considerable amount of energy and power could be saved.