Hydronic HVAC Control for Dew Point and Ventilation Decoupling
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Solution Overview
Problem
Current building energy management systems face challenges such as high energy consumption, poor indoor environmental quality, and vulnerability to terrorist attacks due to inefficient forced air HVAC systems, while hydronic systems are hindered by high costs and lack of effective controls, leading to limited market adoption and energy savings potential.
Innovation Solution
The Hydronic Building Systems Control (HBSC) is a low-cost, software-based control system that integrates traditional and renewable hydronic components for heating, cooling, and hot water, using commodity hardware and BACnet protocol, providing interoperability and advanced algorithms for optimal energy efficiency and comfort, decoupling heating and cooling from ventilation air flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If forced air HVAC systems are used, then heating and cooling can be provided, but energy consumption increases and indoor environmental quality deteriorates
Solution Approach 1:
The system separates ventilation air flow from heating and cooling functions. Fresh air is introduced through dedicated outdoor air systems (DOAS) while heating and cooling are provided independently through hydronic systems (radiant floors, walls, or ceilings), eliminating the energy inefficiencies and air quality issues associated with forced air distribution
Solution Approach 2:
The patent transitions from pneumatic (forced air) distribution to hydraulic (hydronic fluid) distribution for heating and cooling. Fluid circulated through radiant surfaces provides thermal comfort without moving large volumes of air, reducing energy consumption and avoiding the air quality degradation caused by forced air systems
2Use of energy by moving object
If hydronic systems are implemented, then energy efficiency improves, but system cost increases
Solution Approach 1:
The control system serves multiple functions: it manages hydronic heating, cooling, hot water, and ventilation integration, and provides monitoring and optimization. This multi-functionality consolidates what would otherwise require multiple separate systems, reducing overall system cost while maintaining energy efficiency
Solution Approach 2:
The system incorporates automated control and optimization algorithms that self-adjust system operation based on environmental conditions and occupancy, eliminating the need for expensive manual intervention and reducing operational costs while maintaining high energy efficiency
3Loss of energy
If ground source heat pumps are used, then peak demand charges are reduced, but initial investment cost increases
Solution Approach 1:
The system pre-cools or pre-heats thermal storage tanks during off-peak hours when electricity rates are lower, so that cooling or heating can be provided during peak demand periods without running expensive peak-load equipment. This shifts energy consumption to off-peak times, reducing peak demand charges while the control system manages the transition
Solution Approach 2:
The system operates ground source heat pumps and thermal storage in periodic cycles, charging storage during off-peak periods and discharging during peak periods. This periodic operation pattern reduces peak demand charges while the control system optimizes the timing to minimize initial investment impact through efficient cycling
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
HBSC reduces energy consumption by optimizing hydronic system performance, improving indoor comfort and safety, and increasing market acceptance of ground source heat pumps and solar thermal technologies, while lowering operating costs and soft costs associated with installation and maintenance.
Implementation Method 1
hydronic coil-to-air heat exchanger
Implementation Method 2
thermally-conductive structure, such as a building floor, wall, or ceiling
Implementation Method 3
applying a temperature variable liquid at a temperature higher than the dew point of the air space to the thermally-conductive structure
Implementation Method 4
applying a temperature variable liquid coolant at a temperature lower than the dew point to the hydronic coil-to-air heat exchanger
Data Source
AI summary
Controlling heating and cooling in a conditioned space utilizes a fluid circulating in a thermally conductive structure in fluid connection with a hydronic-to-air heat exchanger and a ground heat exchanger. Air is moved past the hydronic-to-air heat exchanger, the air having fresh air supply and stale air exhaust. Sensors located throughout the conditioned space send data to a controller. User input to the controller sets the desired set point temperature and humidity. Based upon the set point temperature and humidity and sensor data, the controller sends signals to various devices to manipulate the flow of the fluid and the air in order to achieve the desired set point temperature and humidity in the conditioned space. The temperature of the fluid is kept less than the dew point at the hydronic-to-air heat exchanger and the temperature of the fluid is kept greater than the dew point at the thermally conductive structure.