Using heat recovered from heat source to obtain high temperature hot water
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Solution Overview
Problem
Current high-temperature hot water heating systems, such as those using natural gas or electric heaters, are limited by efficiency and cost, and existing refrigerants in HVAC systems cannot efficiently reach temperatures above 160°F due to decomposition or efficiency issues, making it challenging to achieve high-temperature hot water effectively.
Innovation Solution
The use of a vapor compression refrigeration system with low-pressure refrigerants, such as R-1233zd(E), in a cascade or standalone configuration, to recover waste heat from existing refrigeration cycles and boost water temperatures up to 200°F, offering coefficients of performance (COP) four to nine times greater than traditional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If natural gas or electric hot water heaters are used for high temperature hot water heating, then high temperature hot water can be obtained, but efficiency is limited with low COP values
Solution Approach 1:
The invention recovers waste heat from the HVAC refrigeration cycle's condenser, which would otherwise be rejected to the environment, and uses it to heat water. This converts a harmful waste product (rejected heat) into a beneficial resource (hot water heating), achieving high temperature hot water with much improved energy efficiency and COP values four to nine times greater than traditional methods
Solution Approach 2:
The HVAC system's refrigeration cycle is made multi-functional by adding a water heating function. The condenser serves dual purposes: rejecting heat to the environment for cooling and simultaneously heating water for hot water needs, allowing one system to perform multiple functions and improve overall energy efficiency
2Temperature
If current refrigerants are used in HVAC heat pumps for hot water heating, then heating up to 160 F can be achieved, but higher temperatures cannot be reached due to decomposition or efficiency issues
Solution Approach 1:
The invention changes the operating parameters of the refrigeration cycle by adjusting the condenser temperature and pressure settings to optimize heat transfer efficiency. By carefully controlling these parameters and using proper heat exchanger design, the system can extract heat at temperatures that enable water heating to 200°F while maintaining refrigerant stability and avoiding decomposition
3Temperature
If CO2 hot water heat pumps are used for high temperature hot water, then high temperature can be achieved, but the system becomes very expensive
Solution Approach 1:
The invention makes the system self-service by utilizing the existing HVAC system's waste heat capacity to provide hot water heating. The system serves itself by using its own operational byproduct (condenser heat) to meet additional heating needs, eliminating the requirement for separate expensive high-temperature heat pump systems and reducing overall system cost
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 approach enables efficient heating of water to high temperatures (160°F to 200°F) with improved COP values, reducing energy consumption and costs, and can be applied in various applications including residential, commercial, and industrial uses, enhancing overall building cooling system efficiency.
Implementation Method 1
apparatuses, systems and methods are directed to heating water to a high temperature by using heat, such as may be considered in some instances as waste heat, recovered from a heat source
Implementation Method 2
vapor compression refrigeration system comprised of a compressor, condenser, evaporator, and expansion device
Implementation Method 3
evaporator
Implementation Method 4
condenser
Data Source
AI summary
Heat is recovered from a heat source to heat water to high temperatures. Apparatuses, systems and methods are described to heat water to a high temperature by using heat, such as may be considered in some instances as waste heat, recovered from a heat source. The methods, systems, and apparatuses described utilize low pressure refrigerant(s) as a fluid to provide a refrigeration cycle that utilizes a source of heat to heat water to a high temperature. The refrigeration cycle can be with or without a cascade cycle. The refrigerant cycle in some examples uses an oil free compressor.