Papers by Keyword: Heat Pump

Abstract: For nearly Zero Energy Buildings, it is a challenge to optimize the heat supply of the building based on technologies like heat pumps. Within the project “energy4buildings” a test bench has been realized to create an interface between hardware, located in a laboratory, and a building simulation software. This integrated test bench with a focus on electrical driven heat pumps and chillers can be used to simulate realistic conditions like part load behavior, stand-by-losses, on/off behavior or user-/weather conditions by using different kind of building models. The requirements of the test rig have been realized by using a hardware-in-the loop (HIL) method, which allows real-time tests of embedded devices within a virtual environment under reproducible laboratory conditions. By using the HIL-method, early statements according performance with a reduction of costs under realistic conditions can be made for various devices. This paper describes the implementation of the HIL-interface consisting of hardware, simulation software and data acquisition including an optimization of the behaviour of the control system as well as HIL experiments at varying steady state conditions like temperature tolerance or holding time. Based on the tests both, a comparison of the performance and analyses of deviations between real and simulated value have been made, to make an accurate statement of the behaviour of the system. The knowledge gained in this paper indicates a potential for optimization of the control strategy of some components as well as the improvement of the communication process to make an early estimation regarding performance of the installed device.

Abstract: This study presents a research of envelope systems entailing elements that use and control incident solar energy to deliver renewable thermal or electric energy to the systems providing heating, ventilation and air conditioning to buildings. A simulation model of an office building was developed in the simulation program TRNSYS. A photovoltaic / thermal system was integrated into the building´s southern facade to generate electricity and to increase the temperature of the air flowing through the channel behind the photovoltaic modules. Subsequently, the electricity generated was used to power the heat pump and the warm air was used as the primary fluid for the heat pump to generate thermal energy for space heating in the winter. The useful energy gain and power production increased with increasing length of the photovoltaic modules and the air flow rate through the channel in the periods, when there was enough solar radiation impinging on the facade. In January to April, the benefits of the photovoltaic / thermal system were minor because of the low levels of low solar radiation and insufficient efficiency of the system components.

Abstract: There are many modelling and simulation methods and techniques, which may be used for prediction or reproduction of heat pumps and chillers behaviour. The hardware-in-the-loop method (HIL) is a technique developed to test a system and its elements working real-time to validate simulated values and to determine the actual performance of heating and cooling capability and performance of the whole system under specific conditions. The HIL can also serve as an intermediate step before testing a system in its actual environment providing opportunity to change boundary conditions or use different control mechanisms. This paper deals with the analysis complexity and possible inaccuracies due to communication difficulties between the test rig and simulation software and due to the test rig hydraulic character. We test and compare several simulation and communication variants such as different time step or different steady-state detection methods in order to achieve the most realistic behaviour of the heat pump and the whole system. The main result of this research is enhancement of communication and simulation accuracy and speedup of the whole process.

Abstract: The aim of this paper is to study the methods and develop technological scheme for thermal energy removal from coal mine rock waste dumps. The prospects of renewable energy sources development in Ukraine are analyzed. A number of available ways for using the sources of waste heat of mining enterprises, namely: outlet ventilation flow, mine water and other rock waste dumps, are investigated. The technological scheme of heat recovery from rock waste dump using heat pumps, which are component segments of the heat pump geosystem on the basis of borehole underground coal gasification, is developed.

Abstract: The ball bearings are the rotating components which are widely spread to moving parts for all machinery operation in general industry. This paper presents the ball bearing resistance tool which has a proper size and can handle the maximum load of 300 kg by using an electric power. The ball bearing resistance tool was used to test the bearings No. 6011 cm. The series of tests was performed in the ball bearings lubricated; engine oil SAE 10W/40, auto transmission fluid Dexron, and hydraulic oil. The rotational speeds for testing were vary; 500, 600 and 700 rpm respectively. At each speed, there were various weight; 50, 70, 90,110,130,150, and 170 kg respectively. The results show that the hydraulic oil generated the smallest coefficients of friction and energy efficiency for ball bearing operation.

Abstract: Within the present context of the effects of climate changes upon the environment, social and economic framework, but also of the trend of population growth and urban development, ensuring a sustainable, competitive and secure energy development will be possible, primarily, by reducing the negative impact of buildings upon the environment, improving energetic and ecological performances of systems and buildings envelope and promoting renewable sources of energy. In this sense, the paper analyzes, in dynamic simulation regime, performant solutions to reduce the energy consumption for heating energy efficient buildings and greenhouse gas emissions, by harnessing geothermal energy through the use of heat pumps and earth-to-air heat exchangers. The case study starts from an energy efficient building, analyzing the dynamic thermal behavior of the building and then various configurations of earth-to-air heat exchangers in terms of heating potential. For the selection of the optimum solution in terms of coverage of the heating energy demand, different systems combining heat pumps and earth-to-air heat exchangers are studied.

Abstract: The central heating units of buildings are typically replaced every 20 to 30 years. There exists a variety of solutions for fuel-and gas-based units, but it would be advantageous to be able to use renewable energies. This would become possible by the combination of planar carbon-fiber-based infrared (IR) radiant heating foils with a heat pump providing hot water. The main goal of our proposed overall control strategy is to increase the energy efficiency while maintaining the thermal comfort for the residents. We examined the electromagnetic compatibility of the heating foils and simulated the relative contributions of the amount of energy provided by the heat pump and by the heating foils to obtain a maximum coefficient of performance for the combined heating system.

Abstract: Systems of heat consumption of the building with heat pump that uses low-grade heat source are investigated. Effectiveness of heat consumption systems with heat pump is concluded effective for severe climatic conditions prevailing in Russia. Characteristics of heat consumption system with heat pump and the traditional heating system are compared. In this case the heat pump is used the warmth of the environment, that is why considered operating conditions for the autumn and spring. Low inertia of heat systems with heat pump compared to traditional ones during autumn and spring proved.

Abstract: Paper deals with the test procedure for evaluating performance parameters of the heat pump air water system. The objective of measurements was tuning errors and optimizes the work of the whole system. The main aim was to find the most acceptable evaporator with which the heat pump COP reached the best results. Choosing of the evaporator consisted of comparing the operating and performance characteristics of individual exchangers.

Abstract: The evaluation of energy flow measurements in two very special buildings under the name of Open Gardens, located in Brno, resulted in confirming that the resources of renewable energy in the Czech Republic can be sufficiently utilized. This energy is derived from photovoltaic elements and earth heat pumps and, additionally, it gets also accumulated in building structures. The energy from renewable resources is utilized for heating, cooling, warm water preparation, for raising air temperature, and it also partially covers the demand for electricity in the building. During the summer period, if the solar gains are considerable, the buildings need being cooled. This is ensured by an earth heat pump enabling the storage of waste heat in deep earth bore holes, offering the advantage of recuperating the heat for heating the rooms during the winter months. At the same time all electricity produced in the building gets utilized, covering roughly 1/3 of the consumption. A plan of comprehensive measurements aiming at the optimization of the most demanding electric appliances has been conceived for this compound of buildings, in order to ensure the best possible utilization of the produced electricity.