Modeling, calibration, and sensitivity analysis of direct expansion AHU-Water source VRF system

Kang, Woo‐Hyoung; Lee, Jong Man; Yeon, Sang Hun; Park, Min Kyeong; Kim, Chul Ho; Lee, Je Hyeon; Moon, Jin Woo

doi:10.1016/j.energy.2020.117435

Cited by 15 publications

(2 citation statements)

References 11 publications

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“…Thus, to prevent this problem and operate the VRF system more efficiently, the compressor current was limited to 50% when the load ratio was 50% or more, based on the calculated indoor heat load. Using this constraint, a VRF system equipped with an inverter could be operated at part load with high efficiency to save energy [20] while suppressing occupants' discomfort by gradually increasing the room temperature without handling all the load. The HVAC system sets the indoor temperature to the highest temperature within the comfortable range and maintains it until the end of the expensive charge period (t3-t4).…”

Section: Overview Of Tou Response Control Algorithmmentioning

confidence: 99%

Annual Effect of the VRF Control Algorithm in Response to the TOU Rate Plan

Lee

Song

2023

Sustainability

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Many countries adopt a time-of-use (TOU) rate system, in which electricity rates vary by season and time of day, to reduce power usage during peak power consumption hours. South Korea offers a TOU rate plan that depends on the electricity usage of a building and its contracted power; in this plan, the electricity rate reaches up to 300% depending on the time of day. Hence, electrically powered variable refrigerant flow (VRF) systems are increasingly being installed in small- and medium-sized buildings requiring individual cooling and heating operations. This study aims to develop a new control algorithm to reduce electricity consumption and electricity rates for cooling and heating by VRF systems in university buildings adopting the TOU rate plan and apply it to actual buildings to verify the reduction effect. The proposed control algorithm primarily consists of a module that controls the refrigerant evaporation temperature (cooling) and high pressure (heating) according to the indoor heat load and a module that controls the indoor set temperature based on the hourly electricity rate. The developed algorithm was installed in the controller of a VRF system installed in an actual university building and the annual effect was verified using the method proposed by the International Performance Measurement and Verification Protocol. As a result, power consumption was reduced by 17.8% for heating and 4.0% for cooling due to the application of the control algorithm, and the electricity rates reduced by 19.2% and 7.3%, respectively.

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Section: Overview Of Tou Response Control Algorithmmentioning

confidence: 99%

Annual Effect of the VRF Control Algorithm in Response to the TOU Rate Plan

Lee

Song

2023

Sustainability

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“…In recent years, the scholars have not slowed down their pace in finding different menthods to present the solitary wave solutions in some fields of physical science [1]. Some scholars have put forward effective methods to solve these problems, such as Ma's and Li's changed objective capacity technique [2], Liu's canonical transformation method [3] and trial equation method [4][5][6][7][8][9], Ma's and Zhu's multiple empirical function method [10] and other direct expansion methods [11][12][13][14][15]. Moreover, the exact solutions for some nonlinear differential equations are classifiled by using the complete discrimination system for polynomials [16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Classication of all single travelling wave solutions to DSW equations

Zheng

2022

J. Phys.: Conf. Ser.

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In this paper, the traditional DSW conditions was presented. The nonlinear incomplete differential conditions were converted into common differential conditions through travelling wave transformation, and all the definite voyaging wave arrangements for the traditional DSW conditions can characterized by use a complete separation framework for polynomials. The specific voyaging wave arrangements existed as periodic solutions of geometrical functions and sane numbers, lone wave arrangements, doubly occasional arrangements of elliptic functions.

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