Heat-Medium Air Conditioning Flow Switching for Energy Saving
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Solution Overview
Problem
Existing air-conditioning apparatuses for buildings face issues with refrigerant leakage into indoor spaces, high energy consumption due to long heat medium circulation paths, poor construction ease, high costs, and noise due to secondary medium circulation systems, and inefficient energy use when multiple indoor units are connected.
Innovation Solution
An air-conditioning apparatus with a refrigerant circuit and a heat medium circuit that includes a compressor, heat source side heat exchanger, expansion devices, pumps, and use side heat exchangers, utilizing flow switching devices to control the flow paths between heat exchangers, allowing for heating, cooling, and mixed operation modes with reduced pipe connections and eliminating refrigerant circulation near indoor units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigerant is circulated to indoor units, then cooling and heating functions are achieved, but refrigerant leakage into indoor spaces occurs
Solution Approach 1:
The system is divided into two separate circulation systems: a refrigerant circulation system (outdoor unit only) and a heat medium circulation system (indoor units). The refrigerant remains confined to the outdoor unit while heat medium circulates through indoor units, eliminating refrigerant leakage risk in indoor spaces.
Solution Approach 2:
A heat medium (water or antifreeze solution) is introduced as an intermediary substance to transfer thermal energy from the refrigerant to indoor spaces. The refrigerant heats or cools the heat medium in the outdoor unit, and the heat medium then carries this thermal energy to indoor units without the refrigerant itself entering indoor spaces.
2Adaptability or versatility
If heat medium circulation path is made long to reach indoor units, then heating and cooling functions are provided, but energy consumption for conveyance increases
Solution Approach 1:
The system dynamically adjusts heat medium circulation based on actual demand. Heat medium is circulated only to indoor units that require heating or cooling, and the circulation amount is optimized based on load requirements, reducing unnecessary conveyance energy consumption.
Solution Approach 2:
The system maintains continuous heat medium circulation to active indoor units, ensuring efficient heat transfer without interruption. The heat medium continuously absorbs heat from the refrigerant in the outdoor unit and delivers it to indoor units, maximizing energy utilization efficiency.
3Adaptability or versatility
If four pipes are arranged to connect outdoor unit to indoor units for simultaneous cooling and heating, then flexible temperature control is achieved, but construction complexity increases
Solution Approach 1:
The outdoor unit serves multiple functions simultaneously: it acts as both a heat source for cooling mode and a heat exchanger for heating mode. The same outdoor unit configuration can provide both cooling and heating to different indoor units based on demand, eliminating the need for separate pipe systems for each function.
4Use of energy by moving object
If secondary refrigerant heat exchanger is placed near each indoor unit, then heat transfer efficiency is improved, but refrigerant leakage risk remains and system cost increases
Solution Approach 1:
The refrigerant heat exchange function is extracted from the indoor units and consolidated in the outdoor unit. Only the heat medium circulation system remains in indoor units, eliminating the refrigerant leakage risk associated with having refrigerant heat exchangers near indoor spaces while maintaining heat transfer efficiency through optimized outdoor unit design.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances safety by preventing refrigerant leakage, reduces energy consumption by optimizing flow paths, simplifies construction, lowers costs by eliminating pumps at indoor units, and allows each indoor unit to operate efficiently by avoiding shared heat medium paths, thus achieving improved energy efficiency and ease of construction.
Implementation Method 1
a heat source side heat exchanger (12)
Implementation Method 2
a plurality of pumps (21a, 21b)
Implementation Method 3
a plurality of use side heat exchangers (26a, 26b, 26c, 26d)
Implementation Method 4
a plurality of expansion devices (16a, 16b)
Implementation Method 5
at least a compressor (10)
Data Source
AI summary
To provide an air-conditioning apparatus capable of achieving energy saving. An air-conditioning apparatus controls first heat medium flow switching devices and second heat medium flow switching devices in a heating only operation mode and a cooling only operation mode such that a flow rate through which a heat medium circulates is formed between all of the heat exchangers related to heat medium and at least one of use side heat exchangers.