Contractors throughout the world have been searching for a practical solution to a common problem: how to maintain stable temperatures in refrigeration equipment dispersed through a large corporate campus.

In Ireland, the Irish Agricultural and Food Development Authority (TEAGASC) faced that situation at its Moorepark campus in Fermoy, County Cork. The solution did not deal with compressor changeouts and superheat adjustments. Rather, it made use of an open-standards-based, commercial Internet gateway that enables remote monitoring and control of any electrically powered system or device from any Internet-enabled PC or mobile phone.

TEAGASC maintains several large refrigeration units used to hold microbiology research samples. In the past, the viability of these samples was threatened by deviations in temperature caused by occasional power failures, malfunctioning units, or even by students in the research department leaving the refrigerator doors ajar.

An earlier system required special wiring. Each change in the location of equipment called for extensive rewiring.

So TEAGASC sought another solution that required no new wiring and had the flexibility to accommodate future expansion and change. TEAGASC wanted to be able to centrally monitor and control temperatures to a stable -50°C (-58°F) for 57 refrigerators at dispersed locations throughout the 15-acre campus. It wanted an early warning system that would:

  • Alert facility management of any temperature deviation or power failure;
  • Instigate measures for backup; and
  • Allow the refrigerators to be easily moved without the need for rewiring.
  • The distance between the existing refrigerators was as much as 500 meters. However, future plans include expanding the monitoring and control system to 80 additional sites throughout Ireland.

    To design and implement a system that would meet those requirements, TEAGASC engaged Lighthouse Communications, based in Limerick, Ireland. Lighthouse in turn selected Coactive Networks of Sausalito, CA, to provided open solutions for connecting control systems to networks and the Internet.

    With the Lighthouse installation, refrigerator temperatures are continually monitored in real time. A temperature probe from each refrigerator is connected to a Lighthouse Power Line Advance Controller (PACE). The PACE unit uses a Coactive Connector, which provides a gateway to the devices by means of existing power lines, transforms the raw logged data to Internet Protocol (IP) format, and routes it over the local area network to the server. From there it is logged and routed to different departments for monitoring and analysis.

    In the event of low temperature, high temperature, or power failure, alarms and specific condition warnings are sent immediately to the maintenance team via mobile phones. In the case of power failure, an automatic backup is launched and a battery-backed digital dialer sends a vocalized message to the maintenance engineer.

    The technical flexibility of the current solution has made available a number of options that leverage the same data infrastructure. This has given rise to plans that include the monitoring of ambient temperatures in all main campus buildings, the development of a site-wide data-capture system, and access monitoring for security purposes.

    More information on Coactive can be found at Lighthouse Communications can be reached at

    Publication date: 01/08/2001