Heat Source Device Control Around Secondary Pump Transients

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional heat source systems inaccurately control the number of operating heat source devices due to transient changes in primary pipe flow rate and load values caused by secondary pump operations, leading to inefficient and unstable system operation.

Innovation Solution

A device and method that determine the number of operating heat source devices based on the load device's state prior to changes in secondary pumps, using conditions such as time and pump frequency to stabilize the system, and control a secondary bypass valve to maintain target flow rates, thereby avoiding transient fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the number of operating heat source devices is controlled based on real-time primary pipe flow rate or load values, then the system responds quickly to load changes, but transient fluctuations from secondary pump operations cause inaccurate control decisions

Engineering Contradiction:

ImproveResponse speed to load changesVSAvoidAccuracy of flow rate measurement

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The control device determines the number of operating heat source devices based on the load device state before the secondary pump operation begins, rather than during the transient period. This preliminary determination avoids the inaccurate flow rate measurements that occur during pump startup or shutdown transients

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control device acts as an intermediary that mediates between the secondary pump control and heat source device control. It receives information about secondary pump operations and uses this information to selectively ignore transient flow rate changes when determining heat source device operation, thus protecting the control system from measurement errors

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the number of heat source devices is increased in response to transient flow rate increases, then the system maintains responsiveness, but unnecessary devices are activated causing energy waste and reduced system efficiency

Engineering Contradiction:

ImproveSystem responsivenessVSAvoidEnergy waste from unnecessary device operation

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The control device makes determination decisions based on pre-pump-operation load states, preventing premature activation of heat source devices in response to transient flow rate increases caused by secondary pump startup

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control device continuously monitors both secondary pump operation status and primary pipe flow rate, using this feedback to distinguish between transient fluctuations and genuine load changes, thereby making accurate control decisions that avoid unnecessary energy consumption

Inventive Principle:

Principle #23Feedback

3Ease of manufacture

If heat source devices are controlled independently from secondary pumps, then each component can be optimized separately, but the system experiences instability due to uncoordinated operations

Engineering Contradiction:

ImproveComponent independenceVSAvoidSystem operational stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The control device merges the control functions for heat source devices and secondary pumps into a single coordinated system. It receives operation information from both components and makes integrated control decisions, ensuring that heat source device operation accounts for secondary pump status and vice versa

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The control device serves as an intermediary coordinator between independently manufactured heat source devices and secondary pumps. It maintains their operational independence for manufacturing purposes while establishing coordination for stable system operation through integrated control logic

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10655868B2Device for controlling number of operating heat source devices, heat source system, control method, and program

Publication Date: 2020.05.19 MITSUBISHI HEAVY IND THERMAL SYST

AI summary

A controller for controlling a number of operating heat sources is provided. The controller detects a change in a number of secondary pumps that supply a heat transfer medium to a load device, determines the number of operating heat sources that changes as a load demand of the state of a load device changes, and switches the number of operating heat sources. The controller determines the number of operating heat sources when the change in the number of secondary pumps due to the change in the load demand is detected, and changes the number of heat sources for as long as at least one of a prescribed period has passed from a time when the change in the number of secondary pumps is detected or a prescribed condition with respect to a value that varies due to the change in the number of secondary pumps is satisfied.