Improved Control of Radiator Heating Systems with Thermostatic Radiator Valves without Pre-Setting Function
Abstract
:1. Introduction
2. Case Study
3. Methodology
3.1. Overview of the Research Procedure
3.2. Equations Describing the Operation of the Heating System Used for the Creation of the Thermal-Hydraulic Model
3.3. Expected Daily Average DH Return Temperature from the Actual Building Case
3.4. First Strategy: Low-Flow System Operation
3.5. Second Strategy: High-Flow System Operation
3.6. Weather Compensation Curve Proposal
4. Results from Analysis
5. Test of the Two Strategies in the Actual Heating System
5.1. Temperature Measurements in the Substation, the Risers, and the Radiators of a Few Apartments
5.2. Return Temperature Measurements before Improvements
5.3. Test of the First Strategy: Low-Flow Operation
5.4. Test of the Second Strategy: High-Flow Operation
6. Proposal for the Implementation of the High-Flow Strategy
7. Discussion
8. Conclusions
Author Contributions
Funding
Conflicts of Interest
References
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Strategy | Modeled | Tested |
---|---|---|
Low-flow system operation (by fixing errors and improving the use of TRVs as requirements) | ✓ | ✓ |
High-flow system operation | ✓ | ✓ |
Step 1 | Selection of the supply temperature and the part load () conditions of the case. The design heat output () of each radiator in the system and the design supply and return temperatures are provided by the SH system operator and they are used as inputs for this calculation. |
Step 2 | Calculation of the mass flow rate () and the pressure drop in every radiator, pipe section and the overall system for the reference case of the ideal operation of the system without errors, by using Equations (1)–(11). The minimum required pressure difference of the pump must be equal to the pressure drop of the system. |
Step 1 | Selection of one radiator in every riser with a fully open TRV that leads into an uncontrolled flow. |
Step 2 | Selection of the minimum required pressure difference of the pump (), calculated under the ideal operation of the radiator system, as an input for the mass flow recalculation in the case of a fully open TRV in every riser. |
Step 3 | Iterative recalculation of the mass flow rate () and the pressure drop in every radiator, by using Equations (1)–(12), due to the existence of the uncontrolled flows in the system (), calculated from Equation (12), for the constant pump pressure difference () selected in Step 2. |
Step 4 | Evaluation of the optimal operation of the TRVs in the system, by accepting a minimum pressure drop in every functional TRV () higher than 5 kPa. |
Step 5 | In case there are several TRVs with a pressure drop lower than 5 kPa, a higher pressure difference of the pump (), is selected as an input and the calculation in Step 3 is repeated until the condition in Step 4 is fulfilled. |
Step 6 | When the condition in Step 4 is fulfilled, and the mass flow rate in every radiator () is recalculated due to the existence of uncontrolled flows (, the return temperature from every radiator and the overall return temperature of the system are calculated by using Equation (13). |
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Benakopoulos, T.; Salenbien, R.; Vanhoudt, D.; Svendsen, S. Improved Control of Radiator Heating Systems with Thermostatic Radiator Valves without Pre-Setting Function. Energies 2019, 12, 3215. https://doi.org/10.3390/en12173215
Benakopoulos T, Salenbien R, Vanhoudt D, Svendsen S. Improved Control of Radiator Heating Systems with Thermostatic Radiator Valves without Pre-Setting Function. Energies. 2019; 12(17):3215. https://doi.org/10.3390/en12173215
Chicago/Turabian StyleBenakopoulos, Theofanis, Robbe Salenbien, Dirk Vanhoudt, and Svend Svendsen. 2019. "Improved Control of Radiator Heating Systems with Thermostatic Radiator Valves without Pre-Setting Function" Energies 12, no. 17: 3215. https://doi.org/10.3390/en12173215
APA StyleBenakopoulos, T., Salenbien, R., Vanhoudt, D., & Svendsen, S. (2019). Improved Control of Radiator Heating Systems with Thermostatic Radiator Valves without Pre-Setting Function. Energies, 12(17), 3215. https://doi.org/10.3390/en12173215