In hot and humid climates, a significant part of the energy is used to cool the building. There are several ways to reduce this air conditioning load, but one standout is through the selection and design of the right building envelope and its components. The thermal characteristics of the building envelope, in particular the thermal resistance of the insulation used, have an impact on the thermal and energy performance of building structures. Thermal conductivity, which indicates the ability of heat to move through a material given a temperature difference, is the primary factor affecting the performance of a thermal insulation material. Both temperature and humidity changes can affect a material’s thermal conductivity value, which can then change. In fact, due to the fluctuating ambient air temperature and solar radiation, thermal insulation in buildings is susceptible to significant and continuous temperature variations. Thermal insulation used in building walls and roofs helps to reduce the energy demand of the building. It improves thermal comfort and, if used correctly, reduces the operational cost of the building. The present study has focused on the effects of location and insulation material on the energy performance of a residential building by considering five climatic locations in the Kingdom of Saudi Arabia (KSA). Five commonly used insulation materials with different thermal characteristics, namely polyurethane board (PU), expanded polystyrene (EPS), glass wool (GW), urea-formaldehyde foam (UFF), and expanded perlite (EP), were analyzed under various climatic zones as per the Saudi Building Code 601/602. The selected cities were categorized based on cooling degree days (CDD) and outdoor dry bulb temperature (DBT) as hot, very hot, and extremely hot climatic zones. Insulation improves thermal comfort and, if used correctly, reduces running costs. Experiments were conducted to determine the thermal conductivity, and the energy simulation was performed by employing IES-VE software for various insulation options. The findings indicate that the location has a significant impact on the energy performance of the insulating materials. The energy saving potential of polyurethane board (PU) insulation is more attractive in cities with higher DBTs and CDDs than in cities with lower DBTs and CDDs. The benefit of installing insulation ranged from a 2 to 14% decrease in energy demand for the climate zones studied. The sensitivity analysis showed that the energy saving potential of the insulation materials is sensitive to the set-point temperature (ST) band.
Observing the effect of temperature, concentration, and impurity on the crystal growth rate is accomplished by simulating the growth of sugar crystals. The volume diffusion growth model was used to examine the crystallization process and compare the effect of the three parameters on the growth of sugar crystals. The non-steady-state behavior of the process is examined using MATLAB simulation. A disturbance analysis of temperature, concentration, and impurity has been conducted to demonstrate their impact on the final crystal size of sugar. The findings show that temperature and impurities affect the final sugar crystal size. In addition, the size of crystals can be enhanced by increasing the concentration of sugar solution.
Energy demand and flue gas emissions, namely carbon dioxide (CO2) associated with the industrial revolution have exhibited a continuous rise. Several approaches were introduced recently to mitigate energy consumption and CO2 emissions by either grass root design or retrofit of existing heat exchanger networks (HEN) in chemical process plants. In this work, a combinatorial approach of path combination is used to generate several options for heat recovery enhancement in HEN. The options are applied to successively shift heat load from HEN utilities using combined utility paths at different heat recovery approach temperature (HRAT) considering exchangers pressure drop. Industrial case study for HEN of the preheat train in crude oil distillation unit from the literature is used to demonstrate the approach. The obtained results have been studied economically using the cost targeting of Pinch Technology. As a result, both external energy usage and CO2 emissions have been reduced from a heater device in HEN by 20% and 17%, respectively, with a payback of less than one year.
Current economic uncertainties and tighter environmental regulations has led industries to consider energy conservation projects more seriously. In this paper, the option of varying the process stream temperature has been suggested as a mean of increasing heat recovery for heat exchanger networks (HEN). Alternatives are generated and assessed using a developed approach. Essentially, the approach involves systematic steps in varying the Hot and/or Cold streams' temperature for each stream in a way that increases the heat recovery approach temperature (HRAT), thus allowing more heat to be recovered. Using the combinatorial method of paths combinations, the adjustment of heat loads for hot and cold utilities from the heat load shifting through the heat exchanger network could be made and assessed accordingly. The changes in temperature made to the streams while exploring each alternative has to be kept within small magnitude i.e., around 1–5 °C. A user friendly computer program has been developed for performing the approach in view of the significant number of iterations required. An example is used in this paper to demonstrate the application of the developed approach.