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This paper presents a rule-based (RB) heating, ventilation, and air-conditioning (HVAC) control system using a multi-layer perceptron network, a deep learning algorithm, for estimating dynamic preconditioning time in residential buildings. The proposed system takes advantage of occupancy, indoor temperature, and weather data to make control decisions in buildings. The system performance is evaluated in terms of financial, demand-side management, energy-efficiency, and occupants’ thermal comfort. The proposed approach considers the perfect occupancy prediction assumption to remove the impact of the uncertainty associated with occupancy prediction and to estimate an upper bound limit for the system performance. The system performance is compared with that of conventional rule-based control approaches to show its effectiveness. To select the optimal control system, the TOPSIS method, as a multi-criteria decision-making approach, is employed. The sensitivity of the proposed system to the temperature setback is also assessed by considering conservative, medium, and deep setback bounds. It is demonstrated that the proposed system outperforms other alternatives when the deep and medium bounds are utilized. This study reveals two limitations of occupancy-based control systems by investigating their performance from financial and peak-demand points of view. First, these systems can cause peak-demand issues and increase the on-peak energy consumption by up to 10%. Secondly, employing a conservative setback can significantly decrease the financial merits of the system, leading to a discounted payback period of 10.87 years for implementing smart thermostats.

Roadway lighting was one of the earliest applications for electric lighting technologies. Well-designed roadway lighting offers many benefits and aids the visual tasks of drivers and pedestrians. Currently, the trend of energy management for exterior general lighting has increased in several cities. Generally, high-pressure sodium (HPS) lamps have been the standard throughout Thailand since the 1980s, but the use of HPS lamps has driven high energy consumption. To conserve energy, light emitting diode (LED) street lighting has quickly become a new trend. The primary objective of this paper is to deliver an initial and in-depth assessment of LED technology for roadway lighting applications. This analysis focuses on the performance of LED luminaires compared with the existing standard of HPS cobra-head luminaires in terms of lighting quality, energy savings, power quality, and investment. The analysis is conducted via three components. First, simulation of the roadway lighting quality is performed using the DIALux programme to evaluate and compare with the standard of Thailand. Second, an experimental setup is used to evaluate the energy savings and power quality for cases with and without solar power. Third, the discounted payback period (DPP) criterion and internal rate of return (IRR) are applied to evaluate the investment scenarios. The obtained results conclude that the LED luminaire performs better than the HPS luminaire in terms of power quality and energy savings (energy-efficient index reduction of approximately 40% over the HPS luminaire), which indicates that the utility benefits from use of LED luminaires. However, although the lighting quality results for LED luminaire have values fairly close to that of the standard, the lighting quality should be improved in terms of uniformity. The results obtained from this analysis are expected to help to improve the roadway lighting standard of Thailand in the future.

Rapid increase in cost of power, its shortage and impact on environment, compels us to use innovative energy efficient technologies for space heating/cooling. Reduction in power consumption in vapour compression based conventional air-conditioner with air-cooled condenser is a difficult task especially in hot and humid weather conditions (Central region of India), where the summer temperature sometimes exceeds 46 °C. Power consumption of conventional air-conditioner can be reduced substantially by hybridizing it with earth air heat exchanger system. In the present research, an effort has been made to reduce the power consumption of 1.5 TR window air-conditioner by coupling with earth air heat exchanger system in three different arrangements. When entire cold air from earth air heat exchanger system is supplied to cool the air-conditioner’s condenser coil, the power consumption is found to be reduced significantly in hybrid system as compared to conventional 1.5 TR window air-conditioner. The economic analysis techniques i.e. simple payback period, discounted payback period, net present value and internal rate of return validate that proposed hybrid arrangements are economically viable.

Conceptually, hybrid photovoltaic/thermal (PV/T) system is superior to conventional side-by-side photovoltaic (PV) and solar thermal (ST) system due to the increase of energy output per unit collector coverage area. The current study aims to demonstrate the advantages of applying a liquid-based PV/T system over a side-by-side system in a real office scale building to support its electricity and hot water demand via computer program simulations of the explicit dynamic PV, ST and PV/T system models. Second, an economic analysis considering the time value of money is presented to evaluate the viability of installing a solar collector system with the adoption of PV/T instead of the side-by-side option. The discounted payback period, which has considered the maintenance and parts replacement costs, of the PV/T system design option is found to be encouraging. The sensitivity analysis shows that even under large variations of different factors in the calculation model, positive net present value is dominant in most cases within the analysis time period. The study reflects desirable potential of incorporating of PV/T technologies in real office buildings under subtropical climate region like Hong Kong.

The purpose of this study is the technical and economic evaluation of a typical solar space and water heating system, utilized in an 88 m 2 detached house that is designed according to the latest Greek Regulation on the Energy Performance of Buildings as a means toward Nearly Zero Energy Buildings (NZEB). The analysis was conducted for each of the four climatic zones designated in the Greek Regulation. A financial analysis was performed and the Net Present Value and the Discounted Payback Period (DPBP) were calculated and correlated with the solar systems collector area and the storage tank volume. Furthermore, the annual avoided emissions from the substituted fossil fuels are estimated for the solar systems considered. The analysis demonstrates that the typical solar space and water heating system can provide a viable solution toward NZEB with solar coverage and DPBP being strongly influenced by the climatic zone of the building and the type of fossil fuel substituted. In all cases the solar system covers at least 45% of the total heating loads while the payback period is as low as 4.5 years with an annual abatement of more than 50 t of CO 2 in the worst case scenario.

The envelope of the Main Hall, Shinawatra University has been designed to provide protection from energy gain. According to initial estimates, the Main Hall could achieve an overall thermal transfer value (OTTV) of 10.16 W/m2, which is four times lower than those recommended by the Thai national standard. This study aims to evaluate the actual energy performance of the Main Hall building envelope using field measurements and simulations. The air temperature, surface temperature, and relative humidity were measured at frequent intervals, both indoors and outdoors. Hourly average meteorological data for insolations were utilized in order to calculate the solar gain by light transmission. Based on the empirical data, the energy fluxes through the envelope on eight different orientations were simulated and the average value was found within 7% of the estimated OTTV. Using the same empirical data for the outdoor condition, simulations of other common types of building envelope in Thailand were carried out for comparison. The results of the analysis show that the Main Hall's lightweight and highly insulated building envelope outperforms other commonly used heavyweight envelopes in preventing building energy gain in the hot-humid climate of Thailand. Although the use of the lightweight and highly insulated envelope helps reduce the operating and investment costs of the air conditioning system as well as the cost of building structure, it also increases the investment cost of the envelope substantially. However, the life cycle cost analysis (LCCA) reveals that the life cycle cost (LCC) of the Main Hall envelope is the most economical, and the increased investment cost of the Main Hall envelope requires a discounted payback period of only 3–5 years, depending on the envelope types used in the comparison. Furthermore, it should be noted that greater savings and a more favorable pay back period could be obtained if this highly energy efficient envelope is applied to other typical buildings, especially high-rise structures in urban areas.