(A) study on the development of air-to-water heat pump

다국어 초록 (Multilingual Abstract)

Heating by environmental-friendly energy is a global trend. Many
international agreements, including the Kyoto Protocol, and international
regulations to reduce the greenhouse gas emission and CO2 emission are highly
focused. Heating appliances using fossil fuel, such as gas boiler or oil boiler,
generate heat energy by the combustion process where CO2 emission is inevitable.
To keep the environment green, lots of EU countries pay attention to the heat
pump to replace traditional boilers. Compared to the conventional air-to-air heat
pump which controls temperature of the indoor air based on the energy of the
ambient air, AWHP (Air-to-Water Heat Pump), main topic of this study, takes
energy from the ambient air and controls temperature of the circulating water for
the under floor loops or radiators.
Conventional heat pump and AWHP have common technology foundation as
the vapor-compression cycle, but the difference is that heat load of former is the
air while the latter is the water. The objective of this study is to develop high
efficient AWHP based on optimized vapor-compression cycle design with the
consideration of the heat load. Based on the review of previous researches and
experimental results about the vapor-compression cycle, fundamental design
factors such as selecting proper mechanical components or determining operating
constraints of the actuators of AWHP are decided and optimized by
benchmarking test.
State variables of the vapor-compression cycle are nonlinearly coupled each
other, and it is hard to express mathematical modeling of the system dynamics.
For AWHP system, multiple actuators like the inverter compressor, the electronic
expansion valve, and external fan are integrated and the operation of each
actuators yield the change of the system dynamics. To find target operating point
where the energy efficiency and the heating performance are satisfied, modeling
for the system dynamics is required. Instead of mathematical approach, modeling
and simulation by neural network methodology is considered in this study. The
neural network is designed to reflect characteristics of the vapor-compression
cycle and the causal relations of state variables. Target operating point is searched
by proposed network and validated by actual test. Test result shows dynamic
response of AWHP with a satisfactory degree.

목차 (Table of Contents)

• LIST OF FIGURES ……………………………………………… ⅳ
• LIST OF TABLES ……………………………………………… ⅷ
• Chapter 1. Introduction …………………………………………… 1
• 1.1 Background …………………………………………………… 1
• 1.2 Objective of the study ………………………………………… 7
• Chapter 2. Review on Heat Pump Cycle ………………………… 11
• 2.1 Introduction ………………………………………………… 11
• 2.2 Expansion Device …………………………………………… 13
• 2.3 Evaporator …………………………………………………… 17
• 2.4 Compressor ………………………………………………… 21
• 2.5 Condenser …………………………………………………… 24
• 2.6 Design Procedure …………………………………………… 27
• Chapter 3. Fundamental Design of Air-to-Water Heat Pump Cycle by Empirical Approach …………………………… 30
• 3.1 Introduction ………………………………………………… 30
• 3.2 Plate Heat Exchanger Selection …………………………… 31
• 3.3 Determining Total Amount of Refrigerant ………………… 35
• 3.4 Determining Minimum Operating Range of Electronic Expansion Valve and Compressor ………………………… 39
• 3.5 Determining Operating Range of External Fan ……………… 46
• Chapter 4. Neural Networks based Empirical Model of Air-toWater Heat Pump Cycle …………………………… 48
• 4.1 Introduction ………………………………………………… 48
• 4.2 Generalized Radial Basis Function Network ……………… 49
• 4.3 State Variables of Air-to-Water Heat Pump Cycle ………… 52
• 4.4 Network Configurations …………………………………… 57
• 4.5 System Modeling …………………………………………… 59
• 4.6 Comparison of Network Methodologies …………………… 67
• 4.7 Network Design for Water-side Estimation ………………… 74
• Chapter 5. Finding Target Operating Point of Air-to-Water Heat Pump………………………………………………… 79
• 5.1 Introduction ………………………………………………… 79
• 5.2 Searching Target Operating Point by Iteration Test using Artificial Neural Network …………………………………… 83
• 5.3 Verifying Target Operating Point by Experiment using Air-to-Water Heat Pump …………………………………………… 89
• 5.4 Exergy Analysis …………………………………………… 94
• Chapter 6. Conclusion …………………………………………… 98
• References ………………………………………………………… 100
• Abstract …………………………………………………………… 104