Modular Bathroom Unit With Drain-Water Heat Recovery
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Solution Overview
Problem
Existing residential water heating systems in small homes are inefficient and wasteful, particularly in bathrooms where intermittent hot water use and heat loss are common, and there is a need for a modular, integrated solution to enhance energy efficiency by recovering heat from bathroom waste water.
Innovation Solution
An integrated tub, sink, and toilet unit with a heat pump circuit that extracts heat from drain water using a vapor compression refrigeration cycle, storing it in a pressurized hot water tank, and utilizing waste water for toilet flushing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a heat pump water heater is used to heat water, then energy efficiency is improved, but the adjacent vicinity is cooled which is not desirable in fall, winter, and spring
Solution Approach 1:
The patent captures the waste heat that would otherwise be lost down the drain and converts it into a useful heating source. The heat pump evaporator absorbs heat from the drain water, and the condenser transfers this heat to the water in the storage tank, turning the harmful waste heat into a beneficial resource for water heating.
Solution Approach 2:
The patent introduces a heat pump system with evaporator and condenser as an intermediary between the drain water and the storage tank water. This intermediary device enables efficient heat transfer from the low-temperature waste water to the water requiring heating, overcoming the temperature difference barrier.
2Area of stationary object
If a modular integrated bathroom unit is used for small spaces, then space utilization is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple bathroom fixtures (tub/shower, sink, toilet) and the heat pump water heating system into a single integrated modular unit. This merging of functions into one compact structure reduces the overall space requirement while managing complexity through unified design and pre-integrated components.
Solution Approach 2:
The modular unit is designed to perform multiple functions within a single structure: bathing (tub/shower), washing hands (sink), toilet functions, and hot water heating through the integrated heat pump system. This multi-functionality eliminates the need for separate fixtures and systems, optimizing space in small bathrooms.
3Use of energy by moving object
If waste water heat is actively transferred to incoming potable water, then energy efficiency is improved, but filtration is required for kitchen and washing machine water
Solution Approach 1:
The patent applies different quality requirements to different water sources. Bath tub and shower drain water, which is relatively clean, is used directly as the heat source without filtration. The system is designed to handle this specific type of waste water effectively, while acknowledging that other sources like kitchen and washing machine water would require filtration.
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
Enhances energy efficiency by recovering heat from bathroom waste water, reducing energy consumption, and providing a compact, modular bathroom unit suitable for small spaces.
Implementation Method 1
the system evaporator extracts heat from the drain water
Implementation Method 2
the condenser heats water stored for washing use
Implementation Method 3
Heat pumps are more efficient than direct resistance electric heating devices because they use a vapor-compression process to extract some of the required heat from an available air source
Data Source
AI summary
A modular bathroom unit that includes a tub or shower with an abutting sink and toilet. The unit is energy saving by use of an integrated heat pump that captures heat from bath water and after heat removal uses the water for toilet flushing. Removed heat from the heat pump circuit may be used for hand washing. The unit features two or three linear sides that allow placement in closet-like spaces found in residential construction. To save space, the tub may be shaped with a narrow end for feet and a wider end for a human torso. Either the toilet or the sink may abut the narrow end of the tub.