[L1] 1 Overview [L2] 1) Definition [L4] - A device that absorbs heat from a low-temperature source (such as air, water, or geothermal energy) and transfers it to a high-temperature space, or conversely, dissipates high-temperature heat to a low-temperature area to perform cooling. [L4] - It is called a heat pump because it doesn't create heat by directly burning energy, but rather "pumps" heat from a lower temperature to a higher one, much like a pump lifts water from a low to a high place. [L5] * By changing the refrigerant flow direction via a 4-Way Valve, a single unit can simultaneously function as an air conditioner (cooling) in summer and a boiler (heating) in winter. [L2] 2) Operating Principle (Thermodynamic Cycle) [L4] - Heat pumps operate based on the Vapor Compression Cycle, where the outdoor unit acts as an 'evaporator' and the indoor unit as a 'condenser' during heating operation. [L2] 3) Operating Process; 4-Stage Cycle (Based on Heating Mode) [L4] - Stage 1: Evaporation (Evaporation - Outdoor Unit)** [L5] * Cold liquid refrigerant absorbs heat from the outdoor air (or geothermal source) and evaporates into a gas. Even in sub-zero weather, heat absorption is possible because the refrigerant boils at an even lower temperature. [L4] - Stage 2: Compression (Compression - Compressor)** [L5] * The gaseous refrigerant is highly compressed by the compressor. As pressure increases, molecular collisions cause a rapid rise in temperature (generating high-temperature gas of approximately 80-90℃). **This is the stage where electrical energy is input.** [L4] - Stage 3: Condensation (Condensation - Indoor Unit)** [L5] * The hot refrigerant gas passes through the indoor heat exchanger, releasing heat to the cooler indoor air (heating) and returning to a liquid state. [L4] - Stage 4: Expansion (Expansion - Expansion Valve)** [L5] * The pressure of the liquid refrigerant is reduced (decompression), making it easy to evaporate again. [L1] 2 Energy Consumption Efficiency and COP Analysis [L2] 1) Engineering Meaning of COP [L4] - The key indicator representing the efficiency of a heat pump is the Coefficient of Performance (COP). [L5] * Standard Electric Heater: 1kW of electricity input yields 1kW of heat **COP = 1.0** (100% efficiency). [L5] * Heat Pump: When 1kW of electricity is input to run the compressor, it "pumps" 3kW of heat from the outside, resulting in a total of 4kW of heat. COP = 4.0 (400% efficiency). [L2] 2) Energy Consumption Level [L4] - For the same heating effect, heat pumps can **reduce energy consumption by over 60-70%** compared to electric heaters or gas boilers. [L5] * This difference in COP is precisely why heating systems in recently popularized high-efficiency heat pump dryers and electric vehicles (EVs) significantly boost battery efficiency. [L1] 3 Technical Comparison: Heat Pump vs. Standard Electric Heater [L1] 4 Latest Technology Trends (Advanced Tech) [L2] 1) Cold Climate Heat Pump [L4] - Historically, heat pumps had a drawback where their performance drastically declined below -10 degrees Celsius. [L4] - By applying Vapor Injection technology, which involves injecting additional refrigerant into the middle of the compressor, technology capable of maintaining 100% heating capacity even in extreme cold has been commercialized. [L2] 2) Geothermal and Water Source Heat Pumps [L4] - Instead of air, these systems use consistent-temperature ground (approx. 15℃) or river water as a heat source, achieving **ultra-high efficiency with COP 5.0 or higher** year-round, regardless of external weather conditions. [L2] References [L3] · ASHRAE Handbook - HVAC Systems and Equipment (Chapter on Heat Pumps). [L3] · IEA (International Energy Agency) - The Future of Heat Pumps Report. [L3] · US Department of Energy (DOE) - Heat Pump Systems Principles. [L3] · ISO 13256 (Water-source heat pumps — Testing and rating for performance).