Dynamic Modelling of Building Envelope on Energy Usage

This study investigates the influence of the building envelope on the energy usage of a chosen building using the simulation program TRNSYS. The building located at Carleton University, Ottawa, Canada is a small building retroffited as part of the Natural Resources Canada’s Prefabricated Exterior Energy Retrofit (PEER) project. The project\u27s aim is to develop prefabricated technologies to be used for retroffiting existing building envelopes of homes in Canada. The thermal resistance (RSI) of the existing walls were improved from 1.80 m2K/W to about 6.40 m2K/W after installation of the prefarbricated retrofit wall system. Analytical verification of the whole building performance simulation software is performed using a solitary heat transfer mechanism under simplified boundary conditions with known analytical solution. The warm-up period necessary to ensure heat is distributed in the building thermal mass at the start of the simulation is quantified. The thermal performance of the whole building envelope is quantified using the time-lag effect and decrement factor and energy requirement for heating and cooling

Thermal modelling of a passive style net-zero greenhouse in Alberta: The effect of ground parameters and the solar to air fraction

Agricultural greenhouses can provide a suitable microclimate for crops to thrive under extreme weather conditions. The operations of these greenhouses are expensive due to the energy requirement of the active thermal conditioning systems required to maintain the growing environment for crop production. Engineering of these greenhouses to utilize clean renewable energy sources is critical and necessary to mitigate their carbon footprint, paving the way to a more sustainable agricultural industry. This paper presents numerical modelling of a net-zero passive solar greenhouse in Alberta, Canada with winter temperatures below freezing. The indoor microclimate of the greenhouse is modelled using the detailed radiation model of a transient simulation tool, TRNSYS. The paper investigates the effects of ground parameters and the solar-to-air fraction on the numerical results. The paper includes a cost comparison between crop production in the traditional and passive style greenhouse

Retrofitting buildings with Phase Change Materials (PCM) – The effects of PCM location and climatic condition

This study investigates the potential energy savings of adding a layer of Phase Change Material (PCM) to the wall assembly of a prefabricated retrofit panel for different climates using the dynamic simulation tool, TRNSYS. The paper presents the result of the numerical validation of heat transfer through the wall assembly using experimental data. Simulations were carried out to determine the most suitable location for adding the PCM layer to the retrofit panel. The study was performed in both a cold Canadian climate and a tropical climate to understand the effect of climate on the performance of the PCM. It was determined that for both climates placing the PCM closer to the interior gives the best results. We also performed an economic analysis to determine if the incorporation of PCM is economically feasible

Energy consumption of a building with phase change material walls – The effect of phase change material properties

The use of Phase Change Material (PCM) in the building envelope is a promising technology for providing energy savings. In this study, the effectiveness of incorporation a honeycomb PCM to the walls of a retrofitted building in Ottawa, Canada is investigated in terms of reduction of heat flux through the walls. The climatic condition of Ottawa has a low air temperature of about −14 °C in the winter season. Reduction in the heat flux through the building envelope reduces the energy consumption of the building. PCM melting temperature, peak effective capacity, and the thickness of PCM layer have been varied to study their respective effect on the effectiveness of the PCM. Incorporating 1-cm thick PCM with peak melting temperature of 20 °C gives the best performance for a typical summer day with outdoor temperature varying from 15.0 to 26.5 °C. The heat gain and heat loss through the studied building walls is reduced by 41 % and 96 %, respectively. Also, the results show no further improvement in the PCM effectiveness when the thickness of the PCM layer and the peak effective heat capacity are increased beyond 1 cm and 20 kJkg−1K−1, respectively

Design and Performance Testing of a Solar Water Heater

This work combines flow by natural convection and forced flow in the design of a solar water heater. The solar water heater was designed such that the entire process was powered by solar energy. This study is focused on the efficiency of the system and the output temperature obtained in Edo State, Nigeria, at Latitude 6.540N of the equator. Experimental tests were conducted in the mid rainy season, through the month of June 2017. The result showed the maximum heat rise of 110C and a minimum of 60C . However, the results displayed are the average of each week of the month of June 2017. The overall efficiency of the system was found to be 54.54%, indicating that more improvement is required for increased efficiency and optimum heat supply