PV Water Heating Circuit With Safe DC-AC Switching

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Solution Overview

Problem

Photovoltaic cells cannot be used for water heating due to incompatibility of direct current power with conventional alternating current circuit devices, posing safety concerns for boiler operation.

Innovation Solution

A device that converts and regulates direct current from photovoltaic cells into alternating current for safe water heating, utilizing a contactor, thermal fuse, and thermostats to manage energy distribution between direct and alternating current heating coils, ensuring safe and efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If photovoltaic cells are used to power water heating, then renewable energy utilization is improved, but safety and compatibility with conventional heating devices deteriorate due to direct current incompatibility

Engineering Contradiction:

Improverenewable energy utilizationVSAvoidsafety compatibility

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces a contactor as an intermediary device between the photovoltaic direct current source and the conventional alternating current heating system. The contactor converts direct current to alternating current through its coil activation mechanism, enabling compatibility between incompatible electrical systems while maintaining safety standards for water heating operations

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes electrical parameters by using a contactor to transform direct current from photovoltaic cells into alternating current suitable for conventional heating elements. This parameter transformation allows the same heating infrastructure to accept renewable energy input while maintaining operational safety and compatibility

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If direct current from photovoltaic cells is used for heating, then energy cost is reduced, but device complexity increases due to need for current conversion and safety controls

Engineering Contradiction:

Improveenergy costVSAvoidsystem complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The heating system is designed with multi-functionality to accept both direct current from photovoltaic cells and alternating current from conventional sources. The contactor and associated control devices enable the system to universally process different current types, reducing energy costs from renewable sources while managing complexity through integrated design

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system incorporates automatic control through thermostats and thermal fuses that self-regulate the heating process. These devices automatically switch between direct current and alternating current sources, and control heating intensity based on temperature feedback, reducing the need for complex manual control systems

Inventive Principle:

Principle #25Self-service

3Reliability

If safety controls are added to enable photovoltaic water heating, then operational safety is improved, but ease of manufacture deteriorates

Engineering Contradiction:

Improveoperational safetyVSAvoidmanufacturing simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Safety controls including thermal fuses and thermostats are pre-installed and pre-configured in the heating system before deployment. The contactor is pre-wired with appropriate safety devices, allowing the system to be manufactured as an integrated safe unit rather than requiring complex post-installation safety modifications

Inventive Principle:

Principle #10Preliminary action

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

Enables safe and efficient water heating using photovoltaic energy, allowing for both direct and alternating current sources, providing a cost-effective and environmentally friendly solution with minimal installation impact, capable of returning acquisition costs within 2 to 5 years through energy savings.

Implementation Method 1

Photovoltaic cells use a sunlight energy to produce the direct current

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

the direct current is brought to a terminal of a coil of a contactor... to an inlet terminal of a heating coil of the direct current circuit

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS8536495B2Device for regulated water heating using the energy gained by photovoltaic cells

Publication Date: 2013.09.17 LAKO DANIEL

AI summary

Direct current power gained by photovoltaic cells can be used for heating water in a boiler. Simple installation allows use for domestic or industrial purposes, with a minimal impact to building construction. At the time of lack of sunlight intensity, water heating is provided by gas, or other heating source, or by use of a heating coil supplied by alternating current for that heating. When sunlight intensity is high, the photovoltaic cells of the present invention can be used alone. However, the source of the direct current has to be properly dimensioned in dependence on the volume of the boiler. An output 1 kWh of the source of the direct current gained by photovoltaic cells can be used to heat water of a volume of 100 L.