Tuesday, March 21, 2017

Hybrid Solar TEG Power Systems

hybrid solar PV photovoltaic thermoelectric generator TEG power system
Hybrid system shown in remote installation
Courtesy Gentherm Global Power Technologies
There are remotely located instruments and equipment throughout the world in places without available grid power. A suitable and reliable means to provide electric power is required as a standalone system for each of these instances. Photovoltaics is an obvious choice for power source, but there is another option that may provide substantial benefit for many installations.

A hybrid solar TEG (thermoelectric generator) can overcome some of the shortcomings of a pure PV system by delivering battery charging current during conditions when solar generated power is insufficient. The TEG uses heat from burning fuel to produce electric power, and can deliver charging current when the PV portion of the system fails to provide sufficient output.

  • Extended periods of bad weather. While this scenario can be compensated for with a larger battery array, there is still a limit to the performance period. Larger battery banks increase unit cost, size and weight.
  • Extreme low temperature. Battery capacity decreases during cold weather, requiring a larger battery array to provide design power output and reserve.
  • Low solar exposure during certain times of the year, requiring more solar panels to accomodate the system power requirements during times of reduced sunlight. This increases unit size and capital cost.

Critical power systems must be designed to deliver sufficient power under all environmental conditions that can be experienced at the installation site. This drives pure PV system designers to substantially oversize panel and battery arrays to assure power delivery throughout an entire year. A hybrid solar TEG system does not need to have the enormous headroom built into the design that a pure PV does. The TEG can produce power at a known rate, regardless of the surrounding environmental conditions. The potential benefits from the hybrid power system include: 

  • Reduction in solar panel array size and cost
  • Lower battery count, with reduction in capital cost, replacement cost, unit size and weight
  • Longer battery life
  • Less on-site fuel vs. a conventional fuel-based system
  • No more than once-per-year maintenance visits
  • Increased reliability over a pure PV installation

Share your remote installation power requirements and challenges with a product application specialist and bring the benefits of a hybrid solar TEG power system to your operation.


Thursday, March 9, 2017

Switching Inductive Loads With Relays and Solid State Devices in Process Control

control panel interior process automation and control panel
Switching devices must be properly protected for longevity
We connect a lot of black boxes together in our control systems, not really knowing what goes on inside. There is a basic understanding of function, but maybe not enough knowledge to thoroughly assess all aspects of integrating a device into a train of control system components. We range from novice to seasoned expert, so Acromag, manufacturer and global supplier of I/O devices for process control, has provided a useful application note regarding the protection of devices employed to switch inductive loads.

The application paper provides a good explanation of what an inductive load is, and how it can impact the performance and longevity of a switching device. The document further explains how to offset the potentially damaging impact of an inductive load on a connected switching device, with specific examples and recommendations on how to put the protective measures in place. It is useful information.

The paper is provided below. Share your I/O and other process measurement and control challenges with application specialists, combining your own process knowledge with their product application expertise to develop effective solutions.


Wednesday, March 1, 2017

Selecting the Right Temperature, Pressure, or Differential Pressure Switch

industrial temperature switch pressure switch differential pressure switch
Temperature, pressure, and differential pressure switches come in a wide variety of configurations
Courtesy Ashcroft
Industrial process control applications present dynamic and varied requirements for measuring, monitoring and control. Each point calls for specific evaluation of the information needed from the process point for use in monitoring process performance, or control to be applied at the process point to regulate an outcome. Sometimes, a continuous analog signal is needed to provide indication across a range of values. Other times, it is only necessary to have notification of, or take action when, a certain temperature or pressure related event occurs. In those cases, a simple and reliable device can adequately meet the project requirements.

Temperature, pressure, and differential pressure switches connect to a process and change their switch position when a setpoint condition is reached. The are simple to understand, easy to install, low in cost, and require little maintenance of attention. The switches are available in an extensive array of configurations, with options to fill out almost any application requirement.

Ashcroft, global supplier of temperature and pressure switches, has produced a simplified guide that enables a designer or specifier to quickly focus their search on the right product. It is provided below for your use. Alternately, you can always share your process measurement and control requirements and challenges with product application specialists, combining your own process knowledge with their product expertise to develop effective solutions.