Packaged Terminal Unit Relay Switching for Dual Power Cost Splitting
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Solution Overview
Problem
There is a need for a method to efficiently control a single packaged terminal unit that provides both heating and cooling to an individual housing unit, where the power source selection depends on whether the unit is in heating or cooling mode, allowing for appropriate cost splitting between the facility and the individual unit.
Innovation Solution
The method involves wiring a relay to switch between two power sources based on the thermostat mode setting, where the relay is configured such that the packaged terminal unit is powered by the facility power source during heating mode and by the individual unit power source during cooling mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single packaged terminal unit provides both heating and cooling, then immediate provision of either heating or cooling is achieved, but it becomes difficult to delineate responsibility and split costs between facility and individual unit
Solution Approach 1:
The power supply system is segmented into two separate power sources: a facility power source for heating and an individual unit power source for cooling. The relay device segments the electrical circuit to selectively connect the packaged terminal unit to one power source or the other based on operational mode, enabling clear cost allocation while maintaining immediate provision of either heating or cooling.
2Device complexity
If separate power sources are used for heating and cooling, then cost splitting is achieved, but control complexity increases
Solution Approach 1:
The relay device is configured to automatically select the appropriate power source based on the operational mode signal from the packaged terminal unit. The system performs self-service by autonomously switching between facility and individual unit power sources without requiring manual intervention, thereby achieving cost splitting while maintaining ease of operation.
3Extent of automation
If a relay is used to switch between power sources, then automatic power source selection is achieved, but wiring complexity increases
Solution Approach 1:
The relay device serves multiple functions: it acts as an automatic switch for power source selection, a controller for cost allocation, and a safety device for preventing backfeed. By consolidating these functions into a single multi-functional component, the system achieves automatic power source selection while minimizing wiring complexity compared to using separate devices for each function.
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 solution allows for efficient splitting of electrical costs for heating and cooling, ensuring immediate provision of either heating or cooling to each housing unit while delineating responsibility and costs appropriately between the facility and individual units.
Implementation Method 1
a readily available relay is wired so that two power sources can be separately selected to power the single packaged terminal unit depending on whether the thermostat calls for a heating or cooling mode of operation
Data Source
AI summary
A method and system of controlling a single load by one of two available power sources. More particularly, the wiring and use of a relay to control a power feed to a packaged terminal unit, that provides both heating and cooling to an individual housing unit, from one of two power sources based upon a heating or cooling thermostat mode of operation. The relay is wired and configured so that when the thermostat is in one mode of operation, a primary side of the relay is open, or not complete, the normally-closed contacts are energized, and the packaged terminal unit is powered by one of the first and the second power source; and when the thermostat is in a second mode of operation, the primary side of the relay is triggered, the normally-open contacts are energized, and the packaged terminal unit ingle is powered by the other power source.