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CES Engineering received federal SRED grant
CES Engineering received federal and provincial tax incentive from the Scientific Research and Experimental Development (SR&ED) program for the work related to optimization of the hot water boiler plant operations. Our work qualified under program sector - experimental development- work that achieves technological advancement to create new materials, devices, products, or processes, or improve existing ones.
The Scientific Research and Experimental Development (SR&ED) program is a federal tax incentive program to encourage Canadian businesses of all sizes and in all sectors to conduct research and development (R&D) in Canada that will lead to new, improved, or technologically advanced products or processes. The SR&ED program is the largest single source of federal government support for industrial research and development.
Our experimentation was conducted on the five residential hot water boiler retrofit projects. The projects included replacement of the existing hot water boilers and domestic hot water heaters with new condensing hot water boiler plant.
TECHNOLOGICAL ADVANCEMENTS
The objective of this project is to develop a method for continuous measurement and verification, with reasonable accuracy, of the hot water boiler plants thermal efficiency in situ.
Existing boiler rating systems do not fully describe a boiler actual efficiency under operating conditions. The boiler units are rated under “laboratory settings”, steady state conditions and primarily only for combustion efficiency. Currently precise thermal efficiency ratings are not performed under field conditions because of the inability to control the required parameters and the high cost of performing such an analysis (ASHRAE 2008, 31.5).
Our proposed method for evaluating boiler plant thermal efficiencies is being tested at five high-rise residential hot water boiler plants located in the Lower Mainland (Greater Vancouver). Through experimentation we are trying to achieve the following technological advancement:-
- Proof of concept regarding the methodology for accurately measuring boiler plant thermal efficiency in operating conditions.
- Methodology for calibration of the input parameters used in calculating boiler plant thermal efficiencies.
- Creating baseline performance curve for the boiler plant thermal efficiency
- Utilization of the thermal efficiency performance curve for the calibration of the building energy simulation models.
- Automatic detection about deviation from optimum boiler plant performances.
- Automatic detection about deviation from optimum gas consumption due to other building effects/conditions non-related to boiler plant.
The above listed new technological knowledge is searched through combination of thermodynamic modeling of the boiler plant energy and heat loss balance in real operating condition and data mining supervised modeling on the experimental data gathered from this project.
A set of commercially available permanent temperature, water flow, gas flow and equipment operation status sensors are installed strategically within five boiler plant’s to monitor and collect operation parameters deemed to impact directly or indirectly the boiler plant performance. The thermal efficiency is then calculated from the metering sensors utilizing energy and heat loss balance modeling methods. Supervised data mining analysis on the population of short term interval metered data is applied for generation of thermal efficiency baseline curves based on the boiler plant operation parameters (i.e. part load, return water temperature, boiler cycling, etc).
TECHNOLOGICAL OBSTACLES:
In a course of this project we faced the following challenges and uncertainties:-
- Inexistence of methodology that defines procedures for accurately measuring boiler plant thermal efficiency under operating conditions. The industry has recognized this problem and ASHRAE is attempting to establish a standard and guideline for a boiler’s actual efficiency under operating conditions. ASHRAE established a committee (SPC-155) which is currently developing a method of testing for rating commercial space heating boiler systems. However no results from this committee are made public yet. Gas boilers are generally design – certified by an accredited testing laboratory based on the test conducted in accordance with ANSI Z21.13. These tests are performed under fixed supply and return water temperature difference, steady state and full load operation. Efficiencies published under this procedure are generally not achieved in actual condition (ASHRAE 2008, 31.6). Currently boiler units are rated and tested primarily for combustion efficiencies. The combustion efficiencies do not account for the effectiveness of the boiler unit heat exchanger as well as radiation and convection losses.
- The second technological shortcoming is the uncertainty introduced by approximation in modeling energy balance and heat losses under boiler operating condition. The exact energy model formula describing boiler performance using physical operating parameters does not exist. Boiler energy modelling algorithms are always approximations of true thermal effects.
- Another uncertainty is introduced through metered data collection process. The accuracy of metered data is dependant on the sensors physical characteristics, sources of error and filed calibration methods. Physical sensors bring in fixed errors for the sensor part and associated transducer instruments or transmitters. Fixed and random errors are introduced by data acquisition systems infrastructure, missing and duplicated data samples, etc.
With our proposed methodology we believe that it is possible to detect relations between boiler operating parameters and the overall boiler performance expressed through thermal efficiency. These relations will inversely provide measure of uncertainty of the approximations made through energy balance model and accuracy of collected metered data. We decided to undertake investigation to be able to prove our postulate.
