Expanding Boiler and Electric Heat Pump Efficiency for Domestic Households

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"LabVIEW makes complex and professional user interface design easy."

- Joshua Cain, TBG Solutions

The Challenge:
Designing a system to monitor the efficiency of both a boiler and electric heat pump system working simultaneously in domestic households.

The Solution:
Using LabVIEW and CompactRIO to gather and analyse boiler system thermal efficiency, thermal output, carbon dioxide emissions, and running costs.

Author(s):
Joshua Cain - TBG Solutions

Efficient, Cost-Effective Heating Need

In a typical UK household, more than half the money spent on fuel bills goes towards providing heating and hot water. As fuel costs continue to rise and the importance of reducing carbon dioxide emissions increases, having an efficient and cost-effective heating system is vital.

Nearly all homes in the UK have a central heating system, a boiler and radiators, or electric storage heaters. The most common form of heating in the UK is a single boiler. The boiler simply heats water, which is then pumped through pipes to radiators and taps throughout the house.

Centrica is a multinational utility company that supplies electricity and gas to the United Kingdom and North America. Centrica is dedicated to providing its customers with the most cost-effective and efficient means of heating whilst keeping carbon dioxide emissions at a minimum. The company enlisted the services of TBG Solutions to design and develop a data acquisition system for the household setups in their testing facilities. TBG Solutions is a National Instruments Gold Alliance Partner specialising in using LabVIEW to provide cutting-edge solutions for a variety of industries, including rail, aerospace, defence, power generation, automotive, and general manufacturing.

Boiler System Overview

The system shown in Figure 1 resembles the actual system setup within Centrica testing facilities.

 

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Figure 1. System User Interface

 

The boiler heats water, which is transferred through pipes to the radiators and hot water cylinder. The heat pump is an outdoor unit that extracts free, low-temperature heat from the surrounding air and increases its temperature. Upgraded heat is then transmitted to the indoor hydrobox. The indoor hydrobox transfers the heat from the heat pump to the water circulating in the central heating radiators and hot water cylinder. The hot water cylinder is a purpose-built stainless steel water tank, constructed to maintain the highest levels of energy efficiency and meet all hot water needs.

The system acquires data and analyzes it to determine whether a boiler, heat pump, or both together is most efficient. A heat pump is more energy efficient and produces fewer carbon emissions than a boiler; however, it cannot instantly produce a significant amount of hot water. Therefore, theoretically combining a heat pump and a boiler would provide the optimal solution for households.

Test System Overview

A cRIO-9074 CompactRIO device acquires data and sends it to a central PC, where operators can view, log, and analyse data. We connected a variety of transducers to the CompactRIO system through C Series analogue (NI 9219) and digital (NI 9375) input modules. We also connected power meters, gas meters, resistance temperature detector (RTD) temperature sensors, and internal and external temperature and humidity sensors through the analogue module and flow meters via the digital module.

Flow meters require high-speed signal processing by the integrated CompactRIO field-programmable gate array (FPGA). The FPGA provides precise measurements, ensuring that the system does not miss pulses from the flow meters. The flow meters measure the flow of water through various pipes to and from both the boiler and heat pump, calculating the exact volume of water passing through the pipes. The PT1000 RTD temperature sensors measure the water temperature.

Two other pieces of hardware that play vital roles are the gas meter and power meter. One of Centrica’s main objectives is to minimize carbon emissions. By monitoring how much gas and power each device used, the system could calculate the precise amount of carbon dioxide each produced.

The CompactRIO constantly acquires data and continually performs calculations on it while simultaneously streaming it to the host. The host then displays the data on the user interface and saves it to disk in TDM streaming (TDMS) format. Operators can later view and analyse the data using DIAdem software.

Conclusion

Centrica can use the system to acquire data from a multitude of sensors, display this data on a GUI, and save it to TDMS files. This was particularly important so that Centrica could later analyse the data files using DIAdem.

The system seamlessly integrates transducers and CompactRIO. Network streams ensure lossless data communication, and LabVIEW makes complex and professional user interface design easy. Furthermore, Measurement and Automation Explorer provides quick and easy testing. TBG Solutions will continue to use NI products and work with Centrica to meet future test and measurement needs.

Author Information:
Joshua Cain
TBG Solutions
3A Midland Court, Barlborough Links
Barlborough S43 4UL
United Kingdom
Tel: 01246 819 100
josh.cain@tbg-solutions.com

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