scholarly journals A study on evaluation systems for optimized design GSHP and ES technologies used in HVAC systems

2021 ◽  
Author(s):  
Ruifang Zhou ◽  
Dejian Gong ◽  
Shengjie Zhu ◽  
Jianchao Ma ◽  
Jiufa Chen
Keyword(s):  
Life Cycle Cost ◽  
Evaluation System ◽  
Operating Cost ◽  
Primary Energy ◽  
Hvac Systems ◽  
Optimized Design ◽  
Fuzzy Evaluation ◽  
Hvac System ◽  
Evaluation Systems ◽  
Annual Operating Cost

Abstract Due to the lack of suitable evaluation systems for heating, ventilation, air-conditioning (HVAC) systems with ground source heat pump (GSHP) and energy storage (ES) technologies, it is difficult to design a building HVAC system to achieve optimized design with regard to investment cost, energy saving and environmental protection. This is a study on developing a fuzzy evaluation system by including GSHP and ES with comprehensively determined weights into an HVAC system. A questionnaire method was used and the answers from 21 HVAC experts were analyzed to facilitate the modeling. Taking a commercial integrated project in Nanjing as an engineering case, the evaluation system was tested. If the system with a comprehensive merit value of 0.303 is adopted, the annual operating cost is reduced by 32.5%, the annual total life cycle cost is reduced by 26.5% and the primary energy consumption and carbon emissions are reduced by 10.5%, with the initial investment increased by 6.5%. This study revealed that the newly developed evaluation system is very useful for realizing the optimal design of HVAC systems.

scholarly journals Modeling and control design of residential HVAC systems for operating cost reduction

2021 ◽  
Author(s):  
Abdul Afram
Keyword(s):  
Complex System ◽  
Energy Consumption ◽  
Operating Cost ◽  
Control Design ◽  
Cost Savings ◽  
Hvac Systems ◽  
Conservation Strategies ◽  
Hvac System ◽  
Modeling And Control ◽  
Supervisory Controller

The residential HVAC systems in Canada can consume more than 60% of the total energy in a house which results in higher operating costs and environmental pollution. The HVAC is a complex system with variable loads acting on it due to the changes in weather and occupancy. The energy consumption of the HVAC systems can be reduced by adapting to the ever changing loads and implementation of energy conservation strategies along with the appropriate control design. Most of the existing HVAC systems use simple on/off controllers and lack any supervisory controller to reduce the energy consumption and operating cost of the system. In Ontario, due to the variable price of electricity, there is an opportunity to design intelligent control system which can shift the loads to off-peak hours and reduce the operating cost of the HVAC system. In order to take advantage of this opportunity, a supervisory controller based on model predictive control (MPC) was designed in this research. The residential HVAC system models were developed and accurately calibrated with the data measured from the Toronto and Region Conservation Authority’s Archetype Sustainable House, House B (TRCA-ASHB) located in Vaughan, Ontario, Canada. Since HVAC is a large and complex system, it was divided into its major subsystems called energy recovery ventilator (ERV), air handling unit (AHU), radiant floor heating (RFH) system, ground source heat pump (GSHP) and buffer tank (BT). The models of each of the subsystem were developed and calibrated individually. The models were then combined together to develop the model of the whole residential HVAC system. The developed model is able to predict the temperature, flow rate, energy consumption and cost for each individual subsystem and whole HVAC system. The model was used to simulate the performance of the existing HVAC system with on/off controllers and develop the supervisory MPC. The supervisory controller was implemented on the HVAC system of TRCA-ASHB and at least 16% cost savings were verified.

scholarly journals Modeling and control design of residential HVAC systems for operating cost reduction

2021 ◽  
Author(s):  
Abdul Afram
Keyword(s):  
Complex System ◽  
Energy Consumption ◽  
Operating Cost ◽  
Control Design ◽  
Cost Savings ◽  
Hvac Systems ◽  
Conservation Strategies ◽  
Hvac System ◽  
Modeling And Control ◽  
Supervisory Controller

The residential HVAC systems in Canada can consume more than 60% of the total energy in a house which results in higher operating costs and environmental pollution. The HVAC is a complex system with variable loads acting on it due to the changes in weather and occupancy. The energy consumption of the HVAC systems can be reduced by adapting to the ever changing loads and implementation of energy conservation strategies along with the appropriate control design. Most of the existing HVAC systems use simple on/off controllers and lack any supervisory controller to reduce the energy consumption and operating cost of the system. In Ontario, due to the variable price of electricity, there is an opportunity to design intelligent control system which can shift the loads to off-peak hours and reduce the operating cost of the HVAC system. In order to take advantage of this opportunity, a supervisory controller based on model predictive control (MPC) was designed in this research. The residential HVAC system models were developed and accurately calibrated with the data measured from the Toronto and Region Conservation Authority’s Archetype Sustainable House, House B (TRCA-ASHB) located in Vaughan, Ontario, Canada. Since HVAC is a large and complex system, it was divided into its major subsystems called energy recovery ventilator (ERV), air handling unit (AHU), radiant floor heating (RFH) system, ground source heat pump (GSHP) and buffer tank (BT). The models of each of the subsystem were developed and calibrated individually. The models were then combined together to develop the model of the whole residential HVAC system. The developed model is able to predict the temperature, flow rate, energy consumption and cost for each individual subsystem and whole HVAC system. The model was used to simulate the performance of the existing HVAC system with on/off controllers and develop the supervisory MPC. The supervisory controller was implemented on the HVAC system of TRCA-ASHB and at least 16% cost savings were verified.

scholarly journals Energy-Optimal Structures of HVAC System for Cleanrooms as a Function of Key Constant Parameters and External Climate

Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 313
Author(s):  
Mieczysław Porowski ◽  
Monika Jakubiak
Keyword(s):  
Optimal Control ◽  
Objective Function ◽  
Energy Demand ◽  
Heat Recovery ◽  
Optimization Procedure ◽  
Simulation Models ◽  
Primary Energy ◽  
Hvac Systems ◽  
Hvac System ◽  
Optimal Structures

This article presents approximating relations defining energy-optimal structures of the HVAC (Heating, Ventilation, Air Conditioning) system for cleanrooms as a function of key constant parameters and energy-optimal control algorithms for various options of heat recovery and external climates. The annual unit primary energy demand of the HVAC system for thermodynamic air treatment was adopted as the objective function. Research was performed for wide representative variability ranges of key constant parameters: cleanliness class—Cs (ISO5÷ISO8), unit cooling loads —q˙j (100 ÷ 500) W/m2 and percentage of outdoor air—αo (5 ÷ 100)%. HVAC systems are described with vectors x¯ with coordinates defined by constant parameters and decision variables, and the results are presented in the form of approximating functions illustrating zones of energy-optimal structures of the HVAC system x¯* = f (Cs, q˙j, αo). In the optimization procedure, the type of heat recovery as an element of optimal structures of the HVAC system and algorithms of energy-optimal control were defined based on an objective function and simulation models. It was proven that using heat recovery is profitable only for HVAC systems without recirculation and with internal recirculation (savings of 5 ÷ 66%, depending on the type of heat recovery and the climate), while it is not profitable (or generates losses) for HVAC systems with external recirculation or external and internal recirculation at the same time.

scholarly journals A Multi-Timescale Bilinear Model for Optimization and Control of HVAC Systems with Consistency

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 400 ◽  
Author(s):  
Zelin Nie ◽  
Feng Gao ◽  
Chao-Bo Yan
Keyword(s):  
Optimization Model ◽  
Air Conditioning ◽  
State Of The Art ◽  
Hvac Systems ◽  
Practical Significance ◽  
Hvac System ◽  
Bilinear Model ◽  
Optimization And Control ◽  
And Control ◽  
Slow Timescale

Reducing the energy consumption of the heating, ventilation, and air conditioning (HVAC) systems while ensuring users’ comfort is of both academic and practical significance. However, the-state-of-the-art of the optimization model of the HVAC system is that either the thermal dynamic model is simplified as a linear model, or the optimization model of the HVAC system is single-timescale, which leads to heavy computation burden. To balance the practicality and the overhead of computation, in this paper, a multi-timescale bilinear model of HVAC systems is proposed. To guarantee the consistency of models in different timescales, the fast timescale model is built first with a bilinear form, and then the slow timescale model is induced from the fast one, specifically, with a bilinear-like form. After a simplified replacement made for the bilinear-like part, this problem can be solved by a convexification method. Extensive numerical experiments have been conducted to validate the effectiveness of this model.

An Exploration of Provincial Low-Carbon Economy Evaluation System Based on Principal Component-Variable Fuzzy Evaluation

2013 ◽  
Vol 291-294 ◽  
pp. 1562-1567
Author(s):  
Ji Min Hu ◽  
Jian Long Gu ◽  
Chang Cui Hu ◽  
Hai Feng Wang
Keyword(s):  
Evaluation System ◽  
Comprehensive Evaluation ◽  
Principal Component ◽  
Fuzzy Comprehensive Evaluation ◽  
Fuzzy Evaluation ◽  
Low Carbon ◽  
Low Carbon Economy ◽  
Component Variable ◽  
The Status ◽  
Carbon Economy

According to indicators’ information repetition and subjectivity of the indicators’ weight set during the variable fuzzy comprehensive evaluation, Principal Component analysis can help solve the weight of the relative indicators and reduce comprehensive evaluation dimensions of the variable fussy comprehensive evaluation. This paper has made a comprehensive evaluation of the status quo of Yunnan’s low carbon economy development(2005-2009), which turns out to be more practical compared with the mere variable fussy theory analysis, thus, principal component-variable fuzzy evaluation is a kind of feasible way to analyze the regional low carbon development status.

The X factor that can help to motivate Generation Y

2015 ◽  
Vol 23 (1) ◽  
pp. 32-34 ◽  
Author(s):  
S.S. Sreejith
Keyword(s):  
Information Technology ◽  
Performance Evaluation ◽  
Evaluation System ◽  
Evaluation Criteria ◽  
Recognition System ◽  
Information Technology Workers ◽  
Content Type ◽  
Performance Evaluation System ◽  
Evaluation Systems ◽  
Effective Performance

Purpose – Explains why performance evaluation designed for manufacturers is inappropriate for information technology organizations. Design/methodology/approach – Underlines the distinctiveness of the information technology workforce and provides the basis for an effective performance- evaluation system designed for these workers. Findings – Highlights the roles of consensus and transparency in setting and modifying evaluation criteria. Practical implications – Urges the need for a fair and open rewards and recognition system to run in parallel with reformed performance evaluation. Social implications – Provides a way of updating performance evaluation systems to take account of the move from manufacturing to information technology-based jobs in many developed and developing societies. Originality/value – Reveals how best to recognize, reward and assess the performance of information technology workers.

Peak-Shaving Ratio Analysis of the Natural Gas Combined Heat and Power Plant With Distributed Peak-Shaving Heat Pumps

2017 ◽  
Author(s):  
Xiling Zhao ◽  
Xiaoyin Wang ◽  
Tao Sun
Keyword(s):  
Natural Gas ◽  
Heat Source ◽  
Heat Pump ◽  
Gas Turbines ◽  
Heat Load ◽  
Operating Cost ◽  
Heat Pumps ◽  
Optimized Design ◽  
Peak Shaving ◽  
Gas Price

Distributed peak-shaving heat pump technology is to use a heat pump to adjust the heat on the secondary network in a substation, with features of low initial investment, flexible adjustment, and high operating cost. The paper takes an example for the system that uses two 9F class gas turbines (back pressure steam) as the basic heat source and a distributed heat pump in the substation as the peak-shaving heat source. The peak-shaving ratio is defined as the ratio of the designed peak-shaving heat load and the designed total heat load. The economic annual cost is taken as a goal, and the optimal peak-shaving ratio of the system is investigated. The influence of natural gas price, electricity price, and transportation distance are also analyzed. It can provide the reference for the optimized design and operation of the system.

scholarly journals Application of Analytical Hierarchy Process in Teaching Quality Analysis of English Writing

2020 ◽  
Vol 15 (14) ◽  
pp. 137
Author(s):  
Xiaoqin Zhang ◽  
Shengxin Wang ◽  
Yanling Cao ◽  
Guangqi Chen
Keyword(s):  
Analytical Hierarchy Process ◽  
Evaluation System ◽  
Evaluation Method ◽  
Evaluation Model ◽  
Teaching Quality ◽  
Quality Analysis ◽  
English Writing ◽  
Evaluation Systems ◽  
Hierarchy Process

There are two major problems in the evaluation of the teaching quality of English writing: the weak logic of the evaluation system and the low reliability of the evaluation model. To solve the problems, this paper put forward an evaluation method for the teaching quality of English writing based on the analytical hierarchy process (AHP). Firstly, the authors reviewed the current evaluation methods for the teaching quality of English writing. Next, hierarchical evaluation systems were established for the teaching quality of English writing from the perspectives of teachers and students, respectively. After that, the AHP method and the grey theory were introduced to set up an evaluation model for the teaching quality of English writing. Finally, several strategies were presented to improve the teaching quality of English writing. The proposed evaluation systems and model enriched the theories on teaching quality evaluation of English writing, and promoted the teaching quality of English writing.

Sign in / Sign up

Export Citation Format

Share Document