Energy Conservation Enhancement Research Articles

A genetic algorithm-based envelope design optimisation for residential buildings

National energy standards of countries worldwide require a wide range of measures to be used in energy policies. It has become a challenge to fulfil different measures of building envelope design optimisation through enhancement of energy conservation. To overcome this challenge, this study proposes an optimisation model for determining the optimum envelope design of a reference building in four climate regions. The optimisation model utilised a genetic algorithm, as an optimisation tool, and national standards to define the thermal insulation requirements of buildings for energy calculation. The building prototype was analysed to minimise the life-cycle cost (LCC), where building envelope elements – namely, windows, exterior walls, basement floor and ceilings – were included as energy efficiency measures. The results showed how each building element affects energy consumption in different climate regions. Exterior wall insulation was observed to have the maximum impact on the LCC of the whole building, which was followed by the window type selection. An optimally designed residential building was found to spend approximately 20–25% less energy than the limiting values expressed in the national standard. This paper highlights how the optimum design envelope for buildings in various countries and climates can be characterised by the use of the proposed optimisation model.

Influence of CaCO3 pore-forming agent on porosity and thermal conductivity of cellulose acetate materials prepared by non-solvent induced phase separation

Thermal insulation materials with a low thermal conductivity are indeed demanded because they play the main role in the enhancement of energy conservation in various industries, especially lightweight constructive materials. Therefore, tubular cellulose acetate (CA) materials were firstly prepared by non-solvent induced phase separation (NIPS). In the NIPS process, the concentration of CA was varied in a range of 20–40 wt%. Also, the temperature of water used as a non-solvent was studied from 5 °C up to 50 °C. According to the FE-SEM results, the 30 wt% CA solution at 20 °C provides tubular CA materials with a higher porous structure than an original CA material but the pore size is quite larger than the mean free path of air leading to achieve a material with high thermal conductivity. To overwhelmed such a problem, the calcium carbonate (CaCO3) was used to be pore forming agents in order to decrease pore size of prepared CA sheet materials. The amount of CaCO3 particles in the CA sheet materials was varied as 50 and 60 wt% to investigate its effect on porosity and thermal conductivity of the prepared materials. As the results, the CA sheet materials prepared using NIPS process and after removing 60 vol% CaCO3 have an enlargement of pores with a size lower than the mean free path of air. They exhibit high porous materials leading to the reduction of their thermal conductivity, which has the lowest value about 0.043 W/mK. Consequently, the CA materials are potentially applied for constructive materials in order to reduce energy consumption in buildings.

Enhancement of Energy Conservation by Hill Reaction Inhibitors in Isolated Spinach(Spinacia oleracea)Chloroplast Fragments

The effect of diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], desmedipham [ethylm-hydroxycarbanilate carbanilate(ester)], propanil (3′,4′-dichloropropionanilide), and dibromothymoquinone (DBMIB) (2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone) on proton translocation and photophosphorylation in isolated spinach(Spinacia oleraceaL.) chloroplast fragments was investigated. In the absence of added cofactors, O2, or artificial electron acceptors, cyclic electron transport occurred, which was coupled to energy conservation. Under aerobic conditions O2acted as the terminal acceptor in non-cyclic electron transport. Proton translocation and photophosphorylation in the cyclic process were enhanced by diuron, desmedipham, and propanil, while in the non-cyclic process they were inhibited by all three herbicides. DBMIB inhibited proton translocation and photophosphorylation in both processes. Proton translocation and its enhancement increased with increasing light intensities. The finding that the plastoquinone (PQ) antagonist DBMIB disrupted cyclic as well as noncyclic electron flow, while diuron enhanced the cyclic and inhibited the noncyclic process, indicated that the acceptor site for endogenously-cycling electrons must lie between the active site of diuron inhibition and PQ, The close similarity in the behavior of diuron, desmedipham, and propanil suggests that their site of action is the same.