Variable air volume air-conditioning experiment system with advanced controls

Abstract

A heating, ventilation, and air-conditioning (HVAC) system is a multi-variable strongly coupled largescale system that is composed of several sub-systems. Considerable research, simulations, and experiments have been conducted on HVAC control. The optimization control of an HVAC system is now the popular issue. The ultimate goal of this paper was to achieve minimum energy consumption and improve system efficiency. Multi-zone variable air volume and variable water volume air-conditioning systems were developed. The dynamic models of HVAC sub-systems were built by the adaptive directional forgetting method. Control strategies such as the gearshift integral proportional-integral-derivative (PID) controller and self-tuning PID controller were studied in the platform to improve the dynamic characteristics of the HVAC system. System performance was improved. The system saved 18.2% of energy with the integration of iterative learning control and sequential quadratic programming based on the steady-state hierarchical optimization control scheme.

Energy Conservation Potential of Economizer Controls Using Optimal Outdoor Air Fraction Based on Field Study

“…Figure 5 shows that it uses enthalpy as a base, and sets the TRA high limit control. If the RAE and the SAE are 53 kJ/kg (dry-bulb temp: 26 • C, humidity ratio: 10.5 g/kg) and 38.5 kJ/kg (dry-bulb temp: 2 • C, humidity ratio: 7.3 g/kg), respectively, and if the OAE is lower than the SAE (area 3 -OAFC: outdoor air fraction calculation), the optimal OAF can be calculated using Equation (2). In this case, additional mechanical cooling is not considered.…”

“…In this chapter, the optimal OAF of different economizer control types was calculated using operational data in AHU 1 and the Equations (1) and (2). The OAF is very significant in economizer performance calculations to reduce gaps between the TSA and SAE and the TMA and the mixing enthalpy (MAE).…”

“…In 2017, the building sector accounted for 20% of total energy consumption in Korea [1]. HVAC system (i.e., heating, cooling, and ventilation) is a primary driver of energy consumption in commercial buildings [2], which occupied about 45% of the total building energy use [3,4]. However, in most existing buildings, it is challenging to improve HVAC system performance due to the considerable construction costs of installing new systems.…”

“…), the optimal OAF can be calculated using Equation(2). In this case, additional mechanical cooling is not necessary.…”

Sustainability in highrise building design and construction

“…The preconstruction design phase is the main stage for making sustainability decisions in building forms, HVAC installation systems (Meng et al ., ) and building materials. In green building design, life cycle assessment, LCCO 2 and LCC have been advanced to optimize decisions for selecting the best set of practices and trade‐offs among competitive objectives such as costs, environmental benign, energy performance, and available equipment, technologies and resources.…”