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Controlling interest: Stuart Cooper, Solfex Energy Systems, discusses the importance of the correct selection and parameter set up on controls
Controlling interest: Stuart Cooper, Solfex Energy Systems, discusses the importance of the correct selection and parameter set up on controls

Stuart Cooper, Solfex Energy Systems, reports on the importance of the correct selection and parameter set up of controls within solar thermal and heating systems, including the features and benefits of the Prozeda Primos, Grandis HK, Conexio 600 & Convisio controls and software

Solar thermal and multifunctional heating controls are complex and offer many variations of hydraulic layouts. They also offer multiple inputs for various temperature sensors such as hot water store sensors, collector sensors, external temperature sensors for weather compensation, irradiance sensors and also volumetric flow meters. Multiple outputs are also high priority on such a controller to operate electrical valves, standard circulation pumps and also low voltage outputs with Pulsed Width Modulation (PWM) to control high efficiency pumps, back up heat sources and also as an interface to the building management system (BMS) within a commercial installation. Most manufactures of such controls also offer various features such as data logging and web or fixed viewing of the relevant system information the controller is actually serving.

First of all, the correct controller should be selected for the right application and hydraulic schematic which will be installed. Is the solar system a drain back type and can the proposed controller handle such a scheme with the relevant drain back functions? Other considerations should also be given to potential future system changes such as another renewable heat source and how that would be electrically integrated and controlled at a later stage, any potential changes or extensions to the heating circuit zones. Further consideration should also be given if high efficiency pumps are to be used within the system and if the selected controller has designated PWM low voltage outputs to control such pumps.

Once the controller type has been selected and installed, its correct operation solely relies on the commissioning engineer who has set the system parameters. Most of these system parameters should have been agreed at the same time as all the other considerations and approved into the overall system design and set up. The simplest function is the operating principle and most basic such as delta T switch on and off temperatures. In domestic systems the Prozeda default settings of 7K / 3K will suffice but consideration should be made within commercial applications with longer pipe runs for a greater differential of delta T to reduce pump cycling and energy wastage, it can also makes sense on commercial systems with long external pipe runs with an high efficiency external plate heat exchanger to design a bypasses into the flow pipe prior to the plate heat exchanger, using Tyforcor LS for the transfer medium for example. With a frost protection of -28°C the fluid will still be in liquid / slush state beyond -20°C depending on system pressure. In direct winter sunshine solar thermal collector fields will still heat up and function, raising the possibility of circulating sub-zero temperature fluids from long external pipe runs directly through a plate heat exchanger. This can cause significant damage to a plate heat exchanger by freezing the primary direct water and it’s better to recirculate the transfer medium around the collector field to a set higher temperature, prior to diverting around the main plate heat exchanger, this alone requires a more advanced controller with additional outputs to control a divert valve.

Pump speed modulation can also have a positive impact on overall system performance and efficiency by automatically adjusting the volumetric flow rate according to increasing or decreasing differential in delta T, using pump speed modulation also decreases energy consumption and wear and tear on the actual circulation pump because the pump won’t be operating at an higher power setting and then throttled down using regulation. Alternatively, the system hydraulics should be designed and sized accordingly and the correct stage of the pump should be set to overcome pressure loss across the entire circuit and collector field.

Conexio web-module & Convisio software
The comprehensive features of these controls are also enhanced further by the ability to data log along with other various methods of viewing system information. As standard a micro SD card slot is inbuilt into the Primos and Grandis range of controllers, once the SD card is in place this will record all historical system parameters and information which is then available for viewing through Prozeda Convisio software which gives a graphical performance chart from an adjustable date range and can display up to 12 outputs / 27 sensor inputs.  The Prozeda Convisio software is free of charge and is available as a download on the Prozeda or Solfex Energy Systems website and is a good tool for technicians and end users alike to oversee the performance of the system; the data can also be exported to PDF or Excel for file saving or printing or even email sending to a solar thermal technician who can analyse the data and advise if any changes are required.  This data can then be shown on 2D and 3D charts & graphs. In the 2D chart, the operator can select a sensor, for example S1, collector sensor and then zoom in on that time period to get more accurate data from that point of the system.

Technical assistance
Despite a lot of controller options, sometimes the correct product selection can still be daunting, Solfex Energy Systems has three full time solar thermal sales engineers supporting Prozeda products within the UK. They are available to assist installers with not only the correct product to select, but also to technically support and offer training on that product as well as assist with the design of the entire solar thermal system and provide CAD and dimensioning of the entire circuit if required.

Technical data

Prozeda Primos 250

Mechanical data
Size 176 x 162 x 44mm, protection class IP 30, light grey, cover plate Prozeda with 4 centralized operation touch pressure keys.
1 output 230V AC
1 electronic control output PWM and 0-10V analogue
4 temperature inputs PT1000

  • Intuitive operating menu with plain-text, graphic symbols and four operating buttons
  • Illuminated LCD display ( 60 x 45mm )
  • Adjustable control values
  • Intelligent speed control of the solar pump via PWM, analogue signal or 230V block modulation
  • Drain-Back function
  • Tube collector function with adjustable time slots
  • Intelligent primary and secondary charging
  • Integrated operating hours counter for storage tank charging
  • Integrated energy yield measurement (input flow rate)
  • Extensive functions for system monitoring. Malfunctions are shown in the display with corresponding symbols and additional optical signals (blinking backlight)
  • Storage of all values even during a prolonged mains power supply outage
  • Various protection functions, such as system protection, collector protection, anti-freeze protection, re-cooling and flow monitoring
  • RS485-interface (ProBus). Networking of additional Prozeda controllers, remote access to all controller configurations and collected values, data logging, update function etc.
  • Micro SD-Card interface for storing and reading of collected values, operating data and system states (data logging), firmware update, reading and loading of configurations
  • Generous wiring space
  • Two multi-functional controllers (MFR) with three freely selectable controller functions each

Prozeda Primos 600

Mechanical data
Size 176 x 162 x 44mm, protection class IP 30, light grey, cover plate Prozeda with 4 centralized operation touch pressure keys.
4 outputs 230V AC
2 electronic control outputs PWM and 0-10V analogue
1 interface for Grundfos VFS
6 temperature inputs PT1000

  • Intuitive operating menu with plain-text, graphic symbols and four operating buttons
  • Illuminated LCD graphic display ( 60 x 45mm )
  • Adjustable control values
  • Intelligent speed control of the solar pump via PWM, analogue signal or 230V block modulation
  • Drain-Back function
  • Tube collector function with adjustable time slots
  • Intelligent primary and secondary charging
  • Integrated operating hours counter for storage tank charging
  • Integrated energy yield measurement; input flow rate or optional flow meter (Impeller wheel sensor, Grundfos VFS)
  • Extensive functions for system monitoring. Malfunctions are shown in the display with corresponding symbols and additional optical signals (blinking backlight)
  • Storage of all values even during a prolonged mains power supply outage
  • Various protection functions, such as system protection, collector protection, anti-freeze protection, re-cooling and flow monitoring
  • RS485-interface (ProBus). Networking of additional Prozeda controllers, remote access to all controller configurations and collected values, data logging, update function etc.
  • Micro SD-Card interface for storing and reading of collected values, operating data and system states (data logging), firmware update, reading and loading of configurations
  • Generous wiring space

Four multi-functional controllers (MFR) with ten freely selectable controller functions each

Prozeda Conexio  600
The web module conexio 600 enables the remote visualization and remote control of all controller settings, parameters and measurements of Prozeda controllers equipped with the Prozeda Bus (ProBus).
The connection works with any available Internet browser (independently of operating system) on a PC, tablet or Smartphone.
The web module conexio 600 has to be integrated in a local network.

Mechanical data
Size 176 x 162 x 44mm, protection class IP 30, light grey, cover plate Prozeda with 4 centralized operation touch pressure keys.

  • Web browser connection PC – Prozeda controller
  • Connection via LAN, WLAN, UMTS, LTE, Internet
  • Exchange of data in both directions
  • Display, modification, reading and storing of data
  • Visualization and remote control with portable devices like Smartphones, Smart pads or similar internet capable devices
  • Web interface not depending on the type of controller and PC- operating system
  • No software installation necessary
  • Firmware update possibility
  • Data logging
  • High degree of operational safety

Illuminated, high resolution LCD graphic display

Prozeda Convisio software
With the evaluation software Conviso you can display and evaluate logging data of controllers of the Prozeda controller family.
All data can be displayed in graphical form (2D and 3D display) and in tabular form.
You can display two inputs and one output.
The graphical data are displayed for one day each and can be zoomed in and out freely.

The software is available for free (see downloads at the end of this page)

Characteristics

  • Graphical evaluation of all measurement data with curve charts
  • Individually fading in and out of measurement data
  • Zooming in and out, minutes-, hours-, daily-, monthly- and yearly view
  • Displaying of data logging data of controllers of the Prozeda controller family
  • Displaying of 2 sensor inputs
  • Displaying of 1 output
  • Hard copy print
  • .pdf print
  • Displaying in tabular form (Excel export)
  • Graphical display 2D
  • Graphical display 3D