Development of Assessing the Thermal Comfort and Energy Performance for Buildings

Climate change is a growing global concern, threatening the worldwide environment, health, and economy [1]. Buildings, as the main contributor to climate change, account for one-third of global energy consumption and one-quarter of CO₂ emissions [2]. The balance between indoor thermal comfort and energy consumption for heating and cooling is a critical issue in building research. Holistic approaches are required to address accurate predictions and superior solutions. In view of this, numerous pieces of research on comprehensive simulation and advanced technologies are observed to achieve better thermal comfort conditions and efficient energy services in buildings.

This Special Issue on the ‘Development of Assessing the Thermal Comfort and Energy Performance for Buildings’ includes six papers ranging from the evaluation indices, assessment approach, and strategy optimization, which is briefly reported below.

Regarding the indoor environment, air distribution characteristics are one of the key factors determining a favorable indoor environment. Four personalized ventilation (PV) systems for desks are discussed by Conceição and Awbi [3] by comprehensively evaluating the integrated effect of thermal comfort (TC), indoor air quality (IAQ), and Draught Risk (DR). A new index, the Air Distribution Turbulence Index (ADTI), is proposed to obtain an evaluation of TC, IAQ, and DR simultaneously by incorporating the effectiveness parameters of εTC, εAQ, and εDR in the Air Distribution Index (ADI). The impact of the PV geometry, the inlet air velocity, the exhaust air terminal location, and the season’s condition on the ADTI and ADI are numerically evaluated. The results reveal the necessity of determining ADTI for the non-uniform environment, especially when the effect of DR becomes significant.

Generally, overall building performance depends on how heat, air, moisture, and contamination are managed and controlled in buildings. In the serial studies conducted by Heibati et al. [4,5,6], advanced simulation models are developed to address IAQ performance and energy performance simultaneously.

Due to the capabilities of exchanging the control variables of airflow and temperature profile between the CONTAM model and the EnergyPlus model, the co-simulation model is developed to simultaneously perform energy balance and mass balance calculations in the first phase [4], while the moisture transport in the building envelope is not included in the model. Preliminary research could provide better performance prediction to reduce energy consumption and improve IAQ together.

In addition, in order to account for the energy-end IAQ performance with the heat, air, and moisture transport in the building envelope, an integrated model that combines the CONTAM model and the WUFI model is developed. The three balances of heat, moisture, and contaminate flows are simultaneously coupled based on the exchange of airflow rate control variables, including infiltration, natural and mechanical ventilation parameters between heat and moisture flows balance equations in WUFI, as well as contaminant flows balance equations in CONTAM [5].

Furthermore, EnergyPlus, dealing with energy measures, CONTAM, for assessing indoor air quality, and WUFI, which considers the moisture and thermal comfort measures, are coupled together to develop an integrated model. The interconnection is performed based on the simultaneous exchange of airflow and temperature control variables in the sub-models of EnergyPlus, CONATM, and WUFI. Corrections are achieved in the airflows, temperatures, and heating/cooling flows control variables, as compared with the single models of EnergyPlus, CONTAM, and WUFI. A case study has been conducted to verify the accuracy of the present model. The comparisons indicate a high accuracy in predicting building performance for the integrated modeling approaches.

To realize building energy conservation and indoor thermal comfort, research on the optimization of design, operation, and control strategies for HVAC systems in buildings has been extensively conducted.

In Ferdyn-Grygierek et al. [7], the impact of the stochastic behavior of window opening and automatically-controlled mechanical ventilation systems on the indoor thermal conditions and the annual heat demand of Polish dwellings are considered and compared. It is found that opening windows increases the heating demand while contributing to thermal comfort by reducing the discomfort hours by over 90%. It is also recommended that mechanical ventilation systems with variable airflow would be the optimal solution, while it may generate noise problems.

Moreover, Franco et al. [8] discuss the application of control strategies for heating in public buildings with variable occupancy profiles. Different control strategies are investigated, involving a conventional steam boiler or heat pumps as the heating facilities with Variable Air Volume systems, Demand Controlled Ventilation system, by comparing to the benchmark solution with boiler and a Constant Air Volume system. The results highlight that the combination of heat pumps and demand-controlled ventilation could contribute to an energy saving of up to 75% with respect to the conventional heating systems with a boiler and no controlled ventilation.