scholarly journals Assessing the Dynamic Performance of Thermochemical Storage Materials

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2202
Author(s):  
Sara Walsh ◽  
Jack Reynolds ◽  
Bahaa Abbas ◽  
Rachel Woods ◽  
Justin Searle ◽  
...  
Keyword(s):  
Waste Heat ◽  
Dynamic Performance ◽  
Thermal Response ◽  
Reactor Power ◽  
Space Heating ◽  
Moist Air ◽  
Minimal Impact ◽  
Power Profile ◽  
Laboratory Scale Reactor ◽  
Cost Efficient

Thermochemical storage provides a volumetric and cost-efficient means of collecting energy from solar/waste heat in order to utilize it for space heating in another location. Equally important to the storage density, the dynamic thermal response dictates the power available which is critical to meet the varied demands of a practical space heating application. Using a laboratory scale reactor (127 cm3), an experimental study with salt in matrix (SIM) materials found that the reactor power response is primarily governed by the flow rate of moist air through the reactor and that creating salt with a higher salt fraction had minimal impact on the thermal response. The flowrate dictates the power profile of the reactor with an optimum value which balances moisture reactant delivery and reaction rate on the SIM. A mixed particle size produced the highest power (22 W) and peak thermal uplift (32 °C). A narrow particle range reduced the peak power and peak temperature as a result of lower packing densities of the SIM in the reactor. The scaled maximum power density which could be achieved is >150 kW/m3, but achieving this would require optimization of the solid–moist air interactions.

Use of alternative energy sources in protected agriculture

1982 ◽  
Vol 11 (1) ◽  
pp. 16-20 ◽  
Author(s):  
D. Pasternak ◽  
E. Rappeport
Keyword(s):  
Alternative Energy ◽  
Heat Storage ◽  
Waste Heat ◽  
Space Heating ◽  
Energy Sources ◽  
Soil Warming ◽  
Greenhouse Soil ◽  
Geothermal Waters ◽  
Water Curtain ◽  
Alternative Energy Sources

Low temperature energy sources for protected cropping include geothermal waters, waste heat from Industry, and trapped sunshine; application depends on the recovery of heat from circulating warmed water, either via the soil in which the plants are growing or via the air in the greenhouse. Soil warming pipes and ‘water-curtain’ systems of space-heating have shown promise, but heat storage, either for short periods or longer, remains a problem common to all such schemes.

scholarly journals Fixed-Time Sliding-Mode Fault-Tolerant Control of Waste Heat Power Generator Systems

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Zhi Wang ◽  
Yateng Bai ◽  
Jin Xie ◽  
Zhijie Li ◽  
Caoyuan Ma ◽  
...  
Keyword(s):  
Fault Tolerant ◽  
Waste Heat ◽  
Sliding Mode ◽  
Dynamic Performance ◽  
Tracking Error ◽  
Fixed Time ◽  
Fault Estimation ◽  
Actuator Fault ◽  
Heat Power ◽  
Time Control

In order to overcome disturbances such as the instability of internal parameters or the actuator fault, the time-varying proportional-integral sliding-mode surface is defined for coordinated control of the excitation generator and the steam valve of waste heat power generation units, and a controller based on sliding-mode function is designed which makes the system stable for a limited time and gives it good performance. Based on this, a corresponding fault estimation law is designed for specific faults of systems, and a sliding-mode fault-tolerant controller is constructed based on the fixed-time control theory so that the systems can still operate stably when an actuator fault occurs and have acceptable performance. The simulation results show that the tracking error asymptotically tends to be zero, and the fixed-time sliding-mode fault-tolerant controller can obviously improve the dynamic performance of the system.

Dynamic performance of the transcritical power cycle using CO2-based binary zeotropic mixtures for truck engine waste heat recovery

Energy ◽  
2020 ◽  
Vol 194 ◽  
pp. 116825
Author(s):  
Gequn Shu ◽  
Rui Wang ◽  
Hua Tian ◽  
Xuan Wang ◽  
Xiaoya Li ◽  
...  
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Dynamic Performance ◽  
Power Cycle ◽  
Truck Engine

scholarly journals Dynamic thermal response of low-energy residential buildings based on in-wall measurements

2019 ◽  
Vol 111 ◽  
pp. 04002 ◽  
Author(s):  
Kyriaki Foteinaki ◽  
Rongling Li ◽  
Alfred Heller ◽  
Morten Herget Christensen ◽  
Carsten Rode
Keyword(s):  
Air Temperature ◽  
Energy Use ◽  
Residential Buildings ◽  
Measurement Data ◽  
Thermal Response ◽  
Low Energy ◽  
Space Heating ◽  
Internal Wall ◽  
Load Bearing ◽  
Concrete Elements

This study analysed the dynamic thermal response of a low-energy building using measurement data from an apartment block in Copenhagen, Denmark. Measurements were collected during February and July 2018 on space heating energy use, set-points, room air temperature and temperature from sensors integrated inside concrete elements, i.e. internal walls and ceiling, at different heights and depths. The heating system was controlled by the occupants. During February, there were unusually high set-points for some days and a regular heating pattern for some other days. Overheating was observed during July. A considerable effect of solar gain was observed both during winter and summer months. The room air temperature fluctuations were observed at a certain extent inside the concrete elements; higher in the non-load-bearing internal wall, followed by the load-bearing internal wall and lastly by the ceiling. The phenomenon of delayed thermal response of the concrete elements was observed. All internal concrete masses examined may be regarded as active elements and can contribute to the physically available heat storage potential of the building. The study provides deep insight into the thermal response of concrete elements in low-energy residential buildings, which should be considered when planning a flexible space heating energy use.

The Effects of Occupancy and Solar Energy on Homes in the Pacific Northwest Constructed According to Improved Thermal Standards

2020 ◽  
Author(s):  
D. R. Heerwagen ◽  
K. Nicoliasen ◽  
A. F. Emery
Keyword(s):  
Pacific Northwest ◽  
Thermal Response ◽  
Solar Heating ◽  
Space Heating ◽  
Occupant Behavior ◽  
Single Family ◽  
Heating Season ◽  
Heating And Cooling ◽  
Energy Needs ◽  
The Pacific

Abstract The space heating energy needed during the winter heating season in Seattle Washington, USA, was monitored over a 15 year period, 1987–2002. Single family residence houses were constructed to building code standards in force at the time of construction and two more to standards calling for envelopes with improved thermal resistance. Although space conditioning energy needs are strongly affected by occupant behavior, simulations generally ignore the temporal occupant behavior in estimating the energy needed for heating and cooling. Vigorous conservation tactics, which produce a thermal response that is highly transient, can lead to substantially different energy needs. No correlation could be established from the measured space heating when aggressive conservation made use of thermostat setback at every opportunity. In this paper we investigate the effects of occupant behavior and the effect of temporal solar heating of walls in the Seattle area for improved thermal construction.

Design and Performance Analysis on CO2 Combined System in Supermarket

2012 ◽  
Vol 433-440 ◽  
pp. 1219-1225
Author(s):  
Jing Hong Ning ◽  
Sheng Chun Liu
Keyword(s):  
Energy Consumption ◽  
Waste Heat ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Space Heating ◽  
Combined System ◽  
Space Cooling ◽  
Gas Cooling ◽  
And Performance

This paper reports a combined space cooling, space heating, water heating and food refrigeration system (named CO2 combined system) in supermarket. This system using CO2 as the working fluid consists of a two-stage CO2 transcritical cycle used for food refrigeration, a single-stage CO2 transcritical cycle for space cooling in summer and space heating in winter. The waste heat emitted from the CO2 gas cooling in food refrigeration cycle and space cooling and space heating cycles is recovered by heat recover exchanger and is used to provide hot water for space heating and for general usage, such as the catering, the washing and the toilet facilities in the supermarket. So this CO2 combined system improves the coefficient of performance, decreases the energy consumption as well as reduces the heat pollution. Moreover, this CO2 combined system is compared with typical conventional supermarket technology, the results show that the energy consumption of CO2 combined system is reduced largely and energy efficiency is increased obviously. It can be concluded that the CO2 combined system has a good future for protecting environment and saving energy.

scholarly journals Energy consumption and modelling of the climate control system in the electric vehicle

2018 ◽  
Vol 37 (1) ◽  
pp. 519-543 ◽  
Author(s):  
Aisling Doyle ◽  
Tariq Muneer
Keyword(s):  
Control System ◽  
Energy Consumption ◽  
Electric Vehicle ◽  
Waste Heat ◽  
Cooling System ◽  
Weather Conditions ◽  
Mean Bias Error ◽  
Space Heating ◽  
Climate Control ◽  
Heating And Cooling

With the introduction of electric vehicles in the automobile market, limited information is available on how the battery’s energy consumption is distributed. This paper focuses on the energy consumption of the vehicle when the heating and cooling system is in operation. On average, 18 and 14% for the battery’s energy capacity is allocated to heating and cooling requirements, respectively. The conventional internal combustion engine vehicle uses waste heat from its engine to provide for passenger thermal requirements at no cost to the vehicle’s propulsion energy demands. However, the electric vehicle cannot avail of this luxury to recycle waste heat. In order to reduce the energy consumed by the climate control system, an analysis of the temperature profile of a vehicle’s cabin space under various weather conditions is required. The present study presents a temperature predicting algorithm to predict temperature under various weather conditions. Previous studies have limited consideration to the fluctuation of solar radiation space heating to a vehicle’s cabin space. This model predicts solar space heating with a mean bias error and root mean square error of 0.26 and 0.57°C, respectively. This temperature predicting model can potentially be developed with further research to predict the energy required by the vehicle’s primary lithium-ion battery to heat and cool the vehicle’s cabin space. Thus, this model may be used in a route planning application to reduce range anxiety when drivers undertake a journey under various ambient weather conditions while optimising the energy consumption of the electric vehicle.

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