Dynamic Simulation and Experimental Validation of a 35 MW Heat Pump Based on a Transcritical CO2 Cycle

Dynamic Simulation and Experimental Validation of a 35 MW Heat Pump Based on a Transcritical CO2 Cycle PDF Author: Leonhard Wolscht
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Dynamic Simulation and Experimental Validation of a 35 MW Heat Pump Based on a Transcritical CO2 Cycle

Dynamic Simulation and Experimental Validation of a 35 MW Heat Pump Based on a Transcritical CO2 Cycle PDF Author: Leonhard Wolscht
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Transcritical CO2 Heat Pump

Transcritical CO2 Heat Pump PDF Author: Xin-rong Zhang
Publisher: John Wiley & Sons
ISBN: 1118380061
Category : Science
Languages : en
Pages : 320

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Book Description
A timely and comprehensive introduction to CO2 heat pump theory and usage A comprehensive introduction of CO2 application in heat pump, authored by leading scientists in the field CO2 is a hot topic due to concerns over global warming and the 'greenhouse effect'. Its disposal and application has attracted considerable research and governmental interest Explores the basic theories, devices, systems and cycles and real application designs for varying applications, ensuring comprehensive coverage of a current topic CO2 heat transfer has everyday applications including water heaters, air-conditioning systems, residential and commercial heating systems, and cooling systems

Modeling, Validation and Design of Integrated Carbon Dioxide Heat Pumps and Water Heaters

Modeling, Validation and Design of Integrated Carbon Dioxide Heat Pumps and Water Heaters PDF Author: Christopher L. Goodman
Publisher:
ISBN:
Category : Heat exchangers
Languages : en
Pages :

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Book Description
Concern with global climate change has led to the interest in the use of natural refrigerants, such as carbon dioxide, as replacements in heat pump systems. When operating in a transcritical cycle, carbon dioxide heat pumps are well suited for use in high temperature water heating heat pumps. In this work, four systems are analyzed: with and without the use of a suction line heat exchanger, and two water heating schemes. These two schemes involve the heating of water to its desired temperature at a low water flow rate in a single pass through the heat pump, and the heating of water at a high water flow rate, but requiring multiple passes. The performance and resulting heat exchanger size of these four systems is analyzed through the development of an overall system model. This system model uses component-level models that were developed based upon heat exchanger geometry and subsequently validated through experimental testing on a test facility developed for this purpose.

CO2 Refrigeration Cycle and Systems

CO2 Refrigeration Cycle and Systems PDF Author: Xin-Rong Zhang
Publisher: Springer Nature
ISBN: 3031225120
Category : Technology & Engineering
Languages : en
Pages : 355

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Book Description
This book covers the fundamentals and applications of carbon dioxide vapor compression refrigeration thermodynamic cycles. In particular, it presents new application areas, such as making ice and snow in the Winter Olympic Games, food cooling and refrigeration. The book explores the physical and chemical characteristics of CO2 fluid, and the unique traits of its thermodynamic cycle. The contributors explain how CO2 refrigeration is a developing, eco-friendly technology, and emphasize its importance for refrigeration and air-conditioning in the current and future market. This book is a valuable source of information for researchers, engineers and policy makers looking to expand their applicable knowledge of high-potential refrigeration technology using carbon dioxide. It is also of interest to postgraduate students and practitioners looking for an academic insight into the industry’s latest eco-friendly technologies.

Dynamic Modeling and Model-free Real-time Optimization for Cold Climate Heat Pump Systems

Dynamic Modeling and Model-free Real-time Optimization for Cold Climate Heat Pump Systems PDF Author: Wenyi Wang
Publisher:
ISBN:
Category : Air source heat pump systems
Languages : en
Pages :

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Book Description
Air source heat pump (ASHP) has been a well-received technology to provide space and/or water heating for building and industrial applications, while its efficiency and heating capacity can be severely limited when operated in cold climate. Various modifications have been proposed for cold-climate operation of ASHP over the single-stage refrigeration cycle, such as vapor injection techniques and cascade configuration. However, there has been a lack of effective control strategies for such systems to maintain the optimal energy efficiency for operations across different combinations of ambient and load conditions. Previous work has paid great efforts in model based strategies, anchored on deriving system models with simulation and experimental testing. Such approaches can be prohibitively expensive due to the inherent nonlinear nature of refrigeration systems and unmeasurable equipment degradation. This dissertation investigates on model-free control strategies for real-time efficiency optimization for several configurations of cold-climate ASHP, by use of Extremum Seeking Control (ESC). By utilizing periodic dither inputs for online gradient estimation, ESC bears significant robustness against process variation and external disturbance, which has proved to be more advantageous in handling the challenging applications like heating, ventilation and air conditioning (HVAC) systems. Three types of ASHP configurations are studied in this dissertation: the internal heat exchanger vapor injection, flash-tank vapor injection, and cascade configuration. For both vapor injection ASHP configurations, the intermediate pressure setpoint is optimized by standard ESC and Newton-based ESC based on the feedback of the total power consumption, with the constant heating load considered. For the cascade ASHP, multivariable ESC is designed to handle two operational scenarios: minimizing the total power for fixed heating capacity and maximizing the coefficient of performance (COP) for variable heating capacity. For the power based ESC, the manipulated inputs include the intermediate temperature, high temperature cycle superheat and low temperature cycle superheat; while for the COP based ESC, the high- and low-temperature cycle compressor speeds and evaporator fan mass flow rate are adopted as inputs. The proposed ESC strategies are evaluated with Modelica based dynamic simulation models of the three system configurations. Simulations have been conducted under both fixed and realistic ambient temperature profiles. The simulation results show good steady-state and transient performance of real-time efficiency optimization with the proposed strategies, in terms of tracking unknown and dynamic optimum settings.

Heat Pump Controls to Exploit the Energy Flexibility of Building Thermal Loads

Heat Pump Controls to Exploit the Energy Flexibility of Building Thermal Loads PDF Author: Thibault Péan
Publisher: Springer Nature
ISBN: 3030634299
Category : Technology & Engineering
Languages : en
Pages : 213

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Book Description
This book describes different control strategies adapted to heat pumps, at the purpose of increasing energy flexibility in buildings. It reports on the development of both simple rule-based controls (RBC) and advanced model predictive controls (MPC). These are tested and compared in both simulation and experimental setups. The book analyzes in detail all the different steps, including the development and tuning of the controllers, their testing in experimental settings and simulation studies. Bridging between advanced control systems theory concepts and practical needs, and discussing the advantages and main challenges of MPC and RBC controllers in terms of efficiency of heat pump operation, electricity prices, emission values, and users’ comfort, this book offers an in-depth evaluation of innovative control strategies applied to energy demand management in buildings.

A Study of a Transcritical Multi-stage Carbon Dioxide Heat Pump

A Study of a Transcritical Multi-stage Carbon Dioxide Heat Pump PDF Author: Ayman G. M. Ibrahim
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Performance Analysis of a Transcritical CO2 Heat Pump Water Heater Incorporating a Brazed-Plate Gas-Cooler

Performance Analysis of a Transcritical CO2 Heat Pump Water Heater Incorporating a Brazed-Plate Gas-Cooler PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 384

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Book Description
This study focuses on the experimental testing and numerical modeling of a 4.5 kW transcritical CO2 heat pump water heater at Queen's University in the Solar Calorimetry Laboratory. Due to the predicted high heat rejection temperatures in a transcritical vapour-compression cycle, buoyancy driven thermosyphon flow through a brazed-plate gas-cooler was proposed to promote tank stratification and to improve system performance. The performance was evaluated through a series of experimental sensitivity and static tank charge tests. A TRNSYS model was also created and verified to simulate the performance of the system under a detailed user demand schedule for a week of operation. The TRNSYS model used a parametric table created with a steady-state model of the vapour-compression system in EES that was validated against experimental data to a standard error of the Y-estimate of ±0.073 kW for heating capacity, ±1.01°C for gas-cooler exit temperature, and ±0.086 for COP. A series of tank charge tests were conducted under thermosyphon flow and forced flow rates at 1 L/min, 2 L/min, and 4 L/min. The thermosyphon charge test produced the highest level of stratification and a total COP of 3 at an average flow rate of 0.73 L/min. All of the forced convection cases operated with a higher degree of mixing. TRNSYS model simulations with hot water draws found that the thermosyphon flow configuration performed with a higher degree of stratification under regular user demand while simulations with high flow rates resulted in a mixed tank at a high temperature. Results predicted an 11% reduction in required heat energy input to the storage, a 30% reduction in electrical energy consumption, a 35% reduction in heat loss, and a 29% improvement in COP for the thermosyphon test as compared to the operation with a mixed tank at 4 L/min. The thermosyphon draw test also performed with the lowest average tank temperature, yet produced the highest draw temperatures. Through these results, it was concluded that natural convection operation with brazed-plate gas-coolers can contribute to a better performing system and this flow configuration should be considered in future applications of this technology.

Simulation and Experimental Verification of Vertical Ground-coupled Heat Pump Systems

Simulation and Experimental Verification of Vertical Ground-coupled Heat Pump Systems PDF Author: Stephen Paul Kavanaugh
Publisher:
ISBN:
Category :
Languages : en
Pages : 356

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Energy-based Visualisation of a Transcritical CO2 Heat Pump Cycle

Energy-based Visualisation of a Transcritical CO2 Heat Pump Cycle PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 356

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Book Description
Carbon dioxide (CO2) -- Transcritical heat pump -- Energy-based representation -- Fault detection -- Fault diagnosis -- Fault detection and isolation -- Koolstofdioksied (CO2) -- Transkritiese hittepompstelsel -- Energie-gebaseerde voorstelling -- Foutopsporing -- Foutdiagnose -- Foutdeteksie en isolasie.