Method for reducing condenser size and power on a heat rejection system

Solution Overview

Problem

Conventional heat rejection systems in refrigerant or cooling systems are oversized and overpowered due to sizing for maximum design heat load and ambient temperature, leading to inefficiencies and increased power consumption, especially when heat loads vary significantly over time.

Innovation Solution

A heat transfer system incorporating a thermal energy storage (TES) section with pressure regulating valves and bypass valves to manage heat transfer dynamically, allowing the system to adjust to varying heat loads by using the TES unit as a supplemental heat sink or source, optimizing condenser capacity and reducing the need for oversized components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the heat exchanger system is sized for maximum heat load at continuous duty cycle in maximum expected ambient air condition, then the system can handle peak conditions, but the condensing unit becomes oversized, overweight, and overpowered for non-peak conditions

Engineering Contradiction:

Improvesystem capacity to handle peak heat loadVSAvoidcondenser weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The system pre-chills thermal energy storage media (water or ice) during off-peak hours when cooling demand is low. This preliminary action allows the condensing unit to be downsized because the stored cold energy will be utilized during peak demand periods, eliminating the need for the condenser to be oversized for continuous peak operation.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the heat exchanger system is sized for maximum heat load at continuous duty cycle in maximum expected ambient air condition, then the system can handle peak conditions, but the condensing unit becomes oversized, overweight, and overpowered for non-peak conditions

Engineering Contradiction:

Improvesystem capacity to handle peak heat loadVSAvoidcondenser weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The system pre-chills thermal energy storage media (water or ice) during off-peak hours when cooling demand is low. This preliminary action allows the condensing unit to be downsized because the stored cold energy will be utilized during peak demand periods, eliminating the need for the condenser to be oversized for continuous peak operation.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the heat exchanger system is sized for maximum heat load at continuous duty cycle in maximum expected ambient air condition, then the system can handle peak conditions, but the condensing unit becomes oversized, overweight, and overpowered for non-peak conditions

Engineering Contradiction:

Improvesystem capacity to handle peak heat loadVSAvoidcondenser power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The system pre-chills thermal energy storage media (water or ice) during off-peak hours when cooling demand is low. This preliminary action allows the condensing unit to be downsized because the stored cold energy will be utilized during peak demand periods, eliminating the need for the condenser to be oversized for continuous peak operation.

Inventive Principle:

Principle #10Preliminary action

4Adaptability or versatility

If complex variable-frequency-drive compressors are employed to facilitate heat-rejection capacity control, then heat rejection can be adjusted to match varying heat loads, but the compressor becomes expensive and frequently operates away from peak efficiency

Engineering Contradiction:

Improveheat rejection capacity controlVSAvoidcompressor power consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by stationary object

Solution Approach 1:

The system pre-chills thermal energy storage media (water or ice) during off-peak hours when cooling demand is low. This preliminary action allows the condensing unit to be downsized because the stored cold energy will be utilized during peak demand periods, eliminating the need for the condenser to be oversized for continuous peak operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The thermal energy storage media (water or ice) acts as an intermediary between the condensing unit and the cooling load. During peak demand, the stored cold energy is released to supplement the condenser output, allowing the compressor to operate at or near peak efficiency while still meeting the total cooling demand.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effectively manages intermittent and varying heat loads by optimizing condenser capacity and reducing power consumption, resulting in a more efficient and responsive heat transfer process that matches the system's requirements, even during transient conditions.

Implementation Method 1

The condenser may transfer heat out of the primary fluid

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

The TES-section may include a TES unit having an inlet and outlet

Methodology Applied

Scientific EffectThermal energy storage: Thermal Energy Storage

Implementation Method 3

The second pressure regulating valve may maintain the primary fluid at the condenser outlet at a first state

Methodology Applied

Scientific EffectPressure regulation:

Implementation Method 4

The TES-section may maintain the primary fluid at the TES section outlet as a liquid-vapor mixture

Methodology Applied

Scientific EffectPhase change: Phase Change

Data Source

PatentUS10921042B2Method for reducing condenser size and power on a heat rejection system

Publication Date: 2021.02.16 ROLLS ROYCE NORTH AMERICAN TECHNOLOGIES INC

AI summary

A heat transfer system for high transient heat loads includes a fluid, a heat exchanger; a compressor downstream of the heat exchanger outlet; a condenser downstream of the compressor outlet, and a thermal energy storage (TES) section downstream of the condenser outlet and upstream of the heat exchanger. The TES section may include a first pressure regulating valve downstream of a TES unit; and a second pressure regulating valve upstream of the first pressure regulating valve.