Hot water heating and storage system
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Solution Overview
Problem
Existing hot water heating and storage systems, particularly in apartment buildings, face challenges in achieving and maintaining high temperatures efficiently due to the inefficiencies of heat pumps, leading to increased legionellosis concerns and limitations in heat transfer and storage capacity.
Innovation Solution
A hot water heating and storage system with an external heat exchanger that increases the heat exchanger surface area, allowing for quicker heating of drinking water and maintaining consistent temperatures between 50°C and 65°C, while using a larger system medium tank to minimize temperature decrease and optimize energy use, especially with heat pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat pumps are used to heat water to high temperatures (55-60°C), then legionella safety is improved, but energy efficiency deteriorates significantly
Solution Approach 1:
The patent implements a tank-in-tank system where the drinking water storage tank is nested inside the system water storage tank. This allows direct thermal coupling between the two water volumes, enabling efficient heat transfer from the system water (heated by heat pump) to the drinking water without requiring the heat pump to directly heat the drinking water to high temperatures, thus maintaining legionella safety while improving energy efficiency
Solution Approach 2:
The system uses system water as an intermediary medium. The heat pump heats the system water, which then acts as a thermal mediator to heat the drinking water in the nested tank through the tank wall. This intermediary approach allows the heat pump to operate at lower temperatures while still achieving the required drinking water temperature for legionella prevention
2Productivity
If tank-in-tank system is used with direct buffer water loading, then heat transfer efficiency is improved, but storage capacity and tap quantity are limited
Solution Approach 1:
The patent adds an external heat exchanger dimension to the system, connecting it to both the system water storage and the drinking water storage tank. This external heat exchange pathway provides an additional dimension for heat transfer, enabling the system to handle larger tap quantities and recharge the drinking water storage more quickly when demand is high, thus overcoming the storage capacity limitation
3Speed
If direct heating of drinking water in heat exchanger is used, then heating speed is improved, but pressure requirement and energy loss increase
Solution Approach 1:
The nested tank configuration allows the drinking water to be heated indirectly through the tank wall by the surrounding system water, eliminating the need for high-pressure direct heat exchanger operation. This reduces pressure requirements and associated energy losses while still providing effective heating
Solution Approach 2:
The system water acts as an intermediary that transfers heat to the drinking water through the tank wall, avoiding the need for direct high-pressure heat exchanger operation. This intermediary heat transfer mechanism reduces pressure requirements and minimizes energy losses associated with high-flow-rate heat exchangers
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
The system enables rapid reheating of large quantities of hot water, maintains consistent temperatures, and reduces energy consumption, while providing hygienic advantages by preventing legionella growth and minimizing sediment accumulation.
Implementation Method 1
The system medium tank is fluidly connected to at least one heat generating device (5) to warm up the system water
Implementation Method 2
The drinking water is heated in the drinking water tank by the heated system medium in the system medium tank. There is therefore a heat exchange from the system water to the drinking water via the wall of the drinking water tank
Implementation Method 3
The said heat exchanger, which is arranged outside the hot water tank, is connected to the drinking water tank in such a way that drinking water, which can be heated by the heat exchanger, is supplied to the drinking water tank
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
A hot water heating and storage system (1) comprises at least one hot water storage tank (2) with at least one system medium tank (3) for receiving a system medium (S), in particular system water, and a potable water tank (4) arranged in the system medium tank (3) with a potable water inlet (4a) for receiving potable water (T) and a potable water outlet (4b) for supplying heated potable water to a consumer network (15), wherein the system medium tank (3) is fluidically connected to at least one heat generator device (5), wherein the system water can be heated by the at least one heat generator device (5), wherein the potable water (T) in the potable water tank (4) is heated by the heated system medium in the system medium tank (3), wherein the hot water heating and storage system (1) further comprises at least one external heat exchanger (6) for heating potable water (T).wherein the external heat exchanger (6) is arranged outside the hot water storage tank (2), and wherein the external heat exchanger (6) is connected to the drinking water tank (4) in such a way that drinking water (T), which can be heated by the external heat exchanger (6), is supplied to the drinking water tank (4).