Applicability analysis of thermoelectric active condensation prevention system in buildings

Thermoelectric system applications in buildings: A review of key factors and control methods

Based on recent earthquakes experiences in Taiwan, losses do not necessarily result from damages of building structures but non-structural components. For instance, the leakage of the fire protection sprinkler systems in hospitals during small earthquakes could results in shortage of medical function and fire protection, and malfunction and repairs of medical equipment. The break of sprinkler systems caused by strong earthquakes could even harm the life safety. Taking a medium-scale hospital as an example, this research aims to conduct a simplified seismic evaluation method to improve seismic performance of the fire protection sprinkler system in critical buildings. The content of this research is summarized below: 1. Numerical analysis of the sample sprinkler piping system: a detailed numerical model of the fire protection sprinkler system in the sample hospital was established with SAP2000 v.20 software. Proper parameters to simulate the threaded joint of piping and the gap between adjacent partition walls or ceiling systems were proposed and verified by the results of component tests and shaking table tests. Ambient vibration tests in the sample hospital were conducted with velocimeters to clarify the structural characteristics of the building structure and the sprinkler piping system. 2. Fragility analysis of sprinkler piping systems: seismic fragility curves the fire protection sprinkler system in the sample hospital were conducted according to a mount of detailed analysis results and verified by the real damage state under Jiaxian earthquake. The effects of engineering demand parameters and categories of ground motion on fragility results are discussed for three types of failure modes. 3. Simplified seismic evaluation method for sprinkler piping systems: according to the results of shaking table tests and detailed analysis, a reliable simplified evaluation method was established to predict seismic behavior of typical sprinkler piping systems in hospitals by the information obtained from in-situ survey. The conservative level and accuracy of simplified evaluation results were verified by comparing the results of fragility analysis of numerical model and simplified evaluation.

The Analysis and Assessment of Lighting System in Mass Residence Building on the Example of Dormitory in Warsaw

Thermal analysis of a wooden door system with integrated vacuum insulation panels

Solar cooling technologies can play a vital role in renewable energy applications development. Thermoelectric systems have shown promising advantages over traditional refrigeration systems such as high thermal comfort, active adaptability, no moving parts, and refrigerants free. In this work, a novel thermoelectric air-conditioning system (TEACS) driven by photovoltaics (PV) is experimentally and theoretically investigated under the hot climate conditions of Sohag city (30°26′N, 42°31′E), Egypt for air conditioning of a typical small-size office room under different thermal loads. During day time, PV panels produce electricity which utilized to drive the TEACS directly and to charge batteries that store electricity to be exploited during nighttime. Moreover, a numerical model implemented in TRNSYS coupled with MATLAB software is developed to evaluate the performance of the proposed TEACS. The influences of varying the input electric current on the coefficient of performance (COP), cooling capacity, and average air room temperature are also studied. The results showed that a design point with an input current of 2.5 A for a cooling capacity of 30 W could be selected to maximize the cooling performance, in which the COP of the TEACS is found to be 2.2. Moreover, the daily average air temperature of the conditioned room was found to be 23.5, 25.5, 27.5, 28.5, and 30.5 °C for internal thermal loads of 0.0 W, 65.0 W,130.0 W, 195.0 W, and 260.0 W, respectively, at average air intake temperature of 36 °C, daily average input current of 4.28 A and air volume flow rate of 14.4 m3/h. It can be concluded that the TEACS powered by PV could be considered as a proper alternative to the traditional vapor compression systems.

Distributed and localized cooling with thermoelectrics

Numerical evaluation on energy saving potential of a solar photovoltaic thermoelectric radiant wall system in cooling dominant climates

[Abstract] Thermophotovoltaic (TPV) cells convert infrared radiation into electricity. They open up possibility for silent and stand-alone power production in fuel-fired heating furnaces. Similarly, thermoelectric (TE) devices convert thermal energy directly into electricity with no moving parts. However, TE devices have relatively low efficiency for electric energy conversion. In the present study, we proposed and developed a cascading TPV and TE power generation system where the used heat stream is taken from the TPV and applied to the input of a TE converter. A prototype cascading TPV and TE system was built and tested. In the cascading power system, GaSb TPV cells and an integrated semiconductor TE converter were used. We investigated the electric output characteristics of the TPV cells and the TE converter in the system at various operating conditions. Experimental results show that the cascading power generation is feasible and has the potential for certain applications. In addition, system analyses and calculations were made, in an effort to elucidate the thermal to electric energy conversion processes.

This paper presents an experimental exergy analysis of the solar thermal system in the Off-Grid Zero Emissions Building (OGZEB) at the Florida State University in efforts to identify components with major irreversibilities, i.e., exergy destruction. The solar thermal system comprises a series of flat-plate solar thermal collectors and 250-gal sensible thermal energy storage tank, and it is an essential constituent of the OGZEB heating system. In this study, exergy flow and destruction rates throughout the solar thermal system were evaluated using the experimental data obtained on two different days. According to the analysis, the greatest exergy destruction rate was observed in the solar thermal collector as expected, and its average exergetic efficiencies were 7.9% and 6.5% on each respective day. In the thermal energy storage tank, most of the exergy destruction was attributed to the mixing of hot water from the collector with the reservoir. This work serves as an initial step to the integrative thermodynamic optimization of the HVAC system in an off-grid residential building, where most energy is consumed for air-conditioning and heating.

Dynamical simulation of building integrated photovoltaic thermoelectric wall system: Balancing calculation speed and accuracy

The article presents the rationale for the use of thermoelectric systems to provide backup power supply for actuators and automation systems for engineering systems of multistory buildings. The experiments were carried out using the developed stand, which modulated the parameters of the engineering systems of multi-storey buildings. The stand consists of a NEPS-100-220-0.03-UHL4 heating element and a CoolerMasterI30 cooler, the temperature on the sides of the thermoelectric module is controlled by a TPM-2 thermostat using a solid-state relay, the thermoelectric power value is recorded by an OVEN IMS device. F1, the electrical load is set by the resistance bridge. Temperature control of thermoelectric elements, hot and cold sides of a thermoelectric module, as well as sources of “heat” and “cold” is carried out by thermocouples, the data is recorded by the TPM138 meter-regulator. As a result of the work carried out, it was found that with the help of new technical solutions it is possible to increase the temperature on the heat exchange sides of thermoelectric modules and bring their technical parameters to the area of maximum efficiency. When organizing thermoelectric systems, it will be possible to provide backup power to the equipment used in heat points of multi-storey buildings.

Sustainable building systems can effectively reduce environmental pressures and mitigate the deterioration of the global climate. The sustainability of complex building systems is influenced by various factors. This article quantitatively analyzes building systems from an ecological emergy and carbon emissions perspective, and considers typical feedback structures’ impact. A neural network algorithm is employed for sustainability prediction analysis. The results demonstrate that both from an emergy and carbon emissions perspective, the operational phase of the building and the production phase of building materials are the main contributors (accounting for over 90%). Among the three types of feedback subsystems, the cross-feedback structure has a more significant impact and yields the best corrective effect. For example, the correction proportion of the building’s emergy sustainability parameter reaches 11.3%, while it is 15.8% for carbon emissions. The neural network model predicts a decreasing trend in the energy sustainability of buildings and increasing carbon emissions over time. To improve the sustainability of building systems, measures such as ecological landscape design and carbon sequestration in building materials are considered, which can enhance the sustainability of buildings to a certain extent.

Air conditioning system has a very important role in a building, this is to support activities in the building. Conventional cooling systems are based on vapor compression systems using refrigerant as the working fluid in the cycle. Commonly used refrigerant fluids have very high global warming and ozone destruction potential. Prolonged use of refrigerants will have negative impacts on the environment such as greenhouse gases and global warming. Through a photovoltaic (PV) system, solar light energy can be converted into electrical energy. Meanwhile, thermoelectric systems can convert temperature differences into electrical voltage differences or vice versa. Hybridization of the two systems can be used as an air conditioning system in buildings or other equipment. In this research, a prototype of a thermoelectric cooling system was produced with an energy source from solar panels, by determining the cooling temperature of a cube-shaped room with a side length of 30 cm at 26oC, the time required to reach this temperature was 18 minutes, data taken starting at 08.00, able to produce an average daily power from solar panels of 54.25 watts at each data collection. Meanwhile, the Coefficient of Performance of the cooling system in this study was 0.305. This system still cannot be compared with conventional cooling systems, but the cooling system in this research has the advantage of being a cooling system that is capable of producing cooling without using an electrical energy source from PLN.

Energy modeling of integrated photovoltaic-thermal panels with thermoelectric systems in buildings

The current study presents the energy and exergy analysis of a thermoelectric waste heat recovery system of an automobile using an aluminum-based heat exchanger. The experiment was conducted on a 4 cylinder direct injection diesel engine by varying the load with constant engine speed. Effect of second law efficiency, availability, entropy generation along with output current, and power of the thermoelectric system on various engine loads have been considered and were compared. Furthermore, the CFD analysis of the heat exchanger of a waste heat recovery system has been considered to evaluate the optimal thickness at the inlet conditions of exhaust gas. On the basis of CFD analysis, the optimal thickness of 3 mm for the heat exchanger has been used for waste heat recovery. The maximum entropy generated by the designed waste heat recovery system is found to be significantly less than the entropy generated by the engine. However, the availability of the exhaust gas is 81.8% higher than the availability of coolant. The study revealed that significant energy is lost through the exhaust, and employing higher load with constant engine speed enhances the scope of waste heat recovery.