Abstract Air Conditioning Research Articles

Performance Improvement of Membrane Energy Exchanger Using Ultrasound for Heating, Ventilation, and Air Conditioning Application

Abstract Air conditioning (AC) systems consume the maximum proportion of the total electricity used in the building sector. The demand for AC systems is expected to increase exponentially in the coming years due to various reasons such as climate change, and an increase in affordability and living floor space. A membrane-based liquid desiccant AC system along with energy recovery ventilating equipment is considered as a prospective alternative to the conventional air conditioning system (CACS). It has the potential to meet the increasing current and future AC demand in a sustainable manner. Its efficiency and energy-saving potential with respect to CACS depend on the performance of the membrane-based dehumidifier, regenerator, and energy recovery ventilating equipment, commonly referred to as membrane energy exchangers (MEEs). MEE is an indirect exchanger type in which a membrane separates the working streams. This intermediate membrane creates an additional resistance for the heat and mass transfer processes in the MEE. To reduce the resistance, this study experimentally and numerically investigate the influence of ultrasound on the performance of the MEE for dehumidification, humidification (applicable for membrane-based evaporative cooling and desiccant regeneration devices), and energy recovery processes. It is found that the vibration due to ultrasound has the potential to improve the mass transfer performance of MEE by the resistance at the air-membrane interface.

Mitigation Options to Reduce Peak Air Temperature and Air-Conditioning Demand in the Context of a Warming Climate for a Tropical Coastal City

Abstract Air conditioning (AC) demand has recently grown to about 10% of total electricity globally, and the International Energy Agency (IEA) predicts that the cooling requirement for buildings globally increases by three-fold by 2050 without additional policy interventions. The impacts of these increases for energy demand for human comfort are more pronounced in tropical coastal areas due to the high temperatures and humidity and their limited energy resources. One of those regions is the Caribbean, where building energy demands often exceed 50% of the total electricity, and this demand is projected to increase due to a warming climate. The interconnection between the built environment and the local environment introduces the challenge to find new approaches to explore future energy demand changes and the role of mitigation measures to curb the increasing demands for vulnerable tropical coastal cities due to climate change. This study presents mid-of-century and end-of-century cooling demand projections along with demand alleviation measures for the San Juan Metropolitan Area in the Caribbean Island of Puerto Rico using a high-resolution configuration of the Weather Research and Forecasting (WRF) model coupled with Building Energy Model (BEM) forced by bias-corrected Community Earth Systems Model (CESM1) global simulations. The World Urban Database Access Portal Tool (WUDAPT) Land Class Zones (LCZs) bridge the gap required by BEM for their morphology and urban parameters. MODIS land covers land use is depicted for all-natural classes. The baseline historical period of 2008–2012 is compared with climate and energy projections in addition to energy mitigation options. Energy mitigation options explored include the integration of solar power in buildings, the use of white roofs, and high-efficiency heating, ventilation, and air conditioning (HVAC) systems. The impact of climate change is simulated to increase minimum temperatures at the same rate as maximum temperatures. However, the maximum temperatures are projected to rise by 1–1.5 °C and 2 °C for mid- and end-of-century, respectively, increasing peak AC demand by 12.5% and 25%, correspondingly. However, the explored mitigation options surpass both increases in temperature and AC demand. The AC demand reduction potential with energy mitigation options for 2050 and 2100 decreases the need by 13% and 1.5% with the historical periods. Overall, the demand reduction potential varies with LCZs showing a high reduction potential for sparsely built (32%), and low for compact low rise (21%) for the mid-of-century period compared with the same period without mitigation options.

Comparing Cooling Energy between Existing Air-Conditioning System and Proposed Design System

Air-conditioning (AC) system is typically used to remove the sensible and latent heat loads in buildings. It provides cool and dehumidified air to meet the occupants comfort and good indoor air quality (IAQ). Improper design and analysis of AC process resulted in high cooling energy and unsatisfied indoor humidity level in tropical climate. The objective of this study is to identify the cooling energy in hotel restaurant by comparing the design with proper fresh air ventilation design. The hotel restaurant was designed with primary air unit (PAU) and air handling unit (AHU) as to remove sensible and latent loads. The performance of the AC system has been monitored and analysed using psychrometric chart. For the AC air side system, 296.2 kW of cooling energy was used in standard operation. An alternative design was proposed for the said hotel restaurant employing only one AHU, with a cooling capacity of 165.9 kW which was 43 % lower than the existing system. The difference in temperature, humidity ratio and air flow rate influenced the cooling energy for AC system.

Energy Consumption Control of an Air Conditioner Using Web Services

Air-conditioning (AC) systems have the highest power consumption among the appliances and consumer devices used at residential homes and buildings. Reducing their energy use will lower peak time usage and lower CO2 emissions. Recently, employment of the Information and Communications Technologies (ICT) to the power grid has smartened the grid. In the smart grid new opportunities emerge for AC energy consumption control. The aim of this paper is to reduce the air conditioning energy consumption of residential customers. It proposes an architecture that provides easy management and control using sensor network web services. A simulation thermal model of a house considers house data and outside temperature is presented. Simulation results showed a proposed temperature control method can have significant energy saving while maintaining customer comfort.