Heating control strategy in fresh air processor matched with variable refrigerant flow air conditioning system

Tu, Qiu; Mao, Shoubo; Feng, Yuhai; Guo, Defang

doi:10.1016/j.enconman.2011.02.007

Cited by 12 publications

(5 citation statements)

References 8 publications

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“…The system principle diagram, installation pattern and principle description are similar to literature. 13 coil temperature sensor Experimental results and discussion. The ambient temperatures of the outdoor chamber and indoor chamber were adjusted to be 7 C DB/ 6 C WB, and 20 C DB/15 C WB, respectively.…”

Section: Experimental Validationmentioning

confidence: 99%

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Investigation of defrosting control function based on model and sequence diagram

Tu¹,

Feng²,

Liu³

et al. 2014

Building Services Engineering Research and Technology

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Defrosting is an important controlled event of variable refrigerant flow air conditioning system (VRF AC). The whole course includes defrosting preparation phase, defrosting execution phase, defrosting end preparation phase and pump-down residual running phase. The defrosting control function can make a great influence on the performance of variable refrigerant flow air conditioning system, whose elements are composed of a certain controlled event, controlled components, executed conditions, controlled time, controlled courses and control logic. A sequence diagram is adopted to express the defrosting dynamic process and the control models of execution conditions on defrosting arrival, defrosting end and pump-down residual running end have been built. Thus, the defrosting control function has been formed based on the model and sequence diagram. The defrosting experiments demonstrate that the built model and sequence diagram can scientifically and accurately express the defrosting control function. Practical application: Defrosting is an important controlled event of variable refrigerant flow air conditioning system. It is difficult to describe the complex controlled course, which is composed of defrosting preparation phase, defrosting execution phase, defrosting end preparation phase and pump-down residual running phase. A sequence diagram can be adopted to express the defrosting dynamic process and the control models of executed conditions on defrosting arrival, defrosting end and pump-down residual running end have been built. Thus, the defrosting control function has been formed based on model and sequence diagram.

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Section: Experimental Validationmentioning

confidence: 99%

“…The system principle diagram, installation pattern and principle description are similar to literature. 13…”

Section: Introductionmentioning

confidence: 99%

Investigation of defrosting control function based on model and sequence diagram

Tu¹,

Feng²,

Liu³

et al. 2014

Building Services Engineering Research and Technology

Self Cite

View full text Add to dashboard Cite

show abstract

“…[14][15][16] Under the conditions of partial load and wide ambient temperatures, the control strategy with variable or dynamic evaporation temperature and condensation temperature can improve EER (in cooling mode) and COP (in heating mode). 6,[16][17][18][19][20][21] For example, Zhao et al 6 presented a control strategy with variable evaporation temperature under partial load conditions to adjust the INV_F. Tu et al 17 built the control model of variable condensation temperature target for the VRF system to improve COP and ensure stable operation at a relatively higher ambient temperature.…”

Section: Introductionmentioning

confidence: 99%

“…6,[16][17][18][19][20][21] For example, Zhao et al 6 presented a control strategy with variable evaporation temperature under partial load conditions to adjust the INV_F. Tu et al 17 built the control model of variable condensation temperature target for the VRF system to improve COP and ensure stable operation at a relatively higher ambient temperature. Tu et al 18 built a dynamic control model of evaporation temperature target to adjust the INV_F of the VRF system with a sub-cooler.…”

Section: Introductionmentioning

confidence: 99%

“…It is adjusted according to a certain evaporation temperature in cooling mode and condensation temperature in heating mode as control objectives, respectively 14–16 . Under the conditions of partial load and wide ambient temperatures, the control strategy with variable or dynamic evaporation temperature and condensation temperature can improve EER (in cooling mode) and COP (in heating mode) 6,16–21 . For example, Zhao et al 6 presented a control strategy with variable evaporation temperature under partial load conditions to adjust the INV_F.…”

Section: Introductionmentioning

confidence: 99%

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Super‐heating degree responsive control strategy of variable refrigerant flow air conditioning system for energy saving and stable operation

Zhang

Yuan³

et al. 2023

Energy Science & Engineering

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The control strategy is important for variable refrigerant flow (VRF) air conditioning system to realize energy saving and stable operation. In this work, the super‐heating degree (SHD) responsive control strategy was developed to dynamically adjust the respective SHD target value (ΔTe,tar) of indoor units so as to adapt to the variable cooling load. The capacity code (Ecode) is introduced into the control model to quantify the reference target value of SHD. To responsively adapt to variable cooling load, the correction target values of SHD based on discharge temperature and deviation of the outlet air temperature are introduced in the SHD model for operation protection of the compressor and the consistency of refrigerant distribution. The enthalpy difference analogy method is developed to estimate the performance of the VRF system including cooling capacity, electric power, and energy efficiency ratio (EER). The performance was tested under the conditions of different ΔTe,tar. Experimental results demonstrate that the ΔTe,tar is an important factor to determine the operation frequency, which affects cooling capacity, power, EER, and operation status of the system. The cooling capacity and electric power at the ΔTe,tar of 9°C was about 55.2% and 63.5% lower than those at the ΔTe,tar of 1°C, and the corresponding EER was improved by 22.6%. To further verify the SHD control strategy, the VRF system was tested by the responsive control model under the condition that Ecode and ΔTe,tar were constantly automatically adjusted and changed with the actual indoor ambient temperature. Experimental results demonstrate that the VRF system can achieve a good and uniform cooling effect and realize energy saving and stable operation according to the responsive super‐heating degree control.

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A comprehensive review of variable refrigerant flow (VRF) and ventilation designs for thermal comfort in commercial buildings

Yau,

Rajput,

Badarudin

2024

J Therm Anal Calorim

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Heating control strategy in fresh air processor matched with variable refrigerant flow air conditioning system

Cited by 12 publications

References 8 publications

Investigation of defrosting control function based on model and sequence diagram

Investigation of defrosting control function based on model and sequence diagram

Super‐heating degree responsive control strategy of variable refrigerant flow air conditioning system for energy saving and stable operation

A comprehensive review of variable refrigerant flow (VRF) and ventilation designs for thermal comfort in commercial buildings

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