Price and capacity are only the starting point when specifying temporary air-conditioning. Marc White looks at the questions that should be asked

Hired air-conditioning equipment may be needed to extend production capacity at peak times, for the piloting of a new product or to cover planned maintenance.

When assessing the most appropriate rental for a job, the factors to consider include:

  • Will the site be surveyed, and will the survey be free?
  • Is the stock equipment adequately maintained and renewed?
  • Does the equipment represent the latest technology?
  • Do the chillers come with multiple circuits so that emergency cover is integral, or will back-up units need to be installed?
  • Do they have a small footprint? Is there a choice?

There are also questions about power supply, such as whether the chillers or air handlers come with their own power supply and whether the equipment operates from the mains supply? Regarding power management, who will be responsible for supplying the fuel for temporary generators, and what happens if a generator fails?

An increasingly important consideration is the reuse and recycling of energy. Carrier Rental Systems has introduced a design change to incorporate return air collection even in the most difficult circumstances, such as large marquees or temporary structures.

Enabling the internal and also the large external air handling plant to recirculate the air means that it isn’t being cooled from ambient every time. There is likely to be several degrees of temperature reduction in the return air which can be used to cut the chiller load. Energy savings of about 50% are being experienced.

Finally, there are quality of service questions. Are you treated as an individual or just another tick in the box? Will there be a supportive relationship, offering not just 24-hour technical support but suggestions about the best way to do something? Is the company constantly introducing innovations? And what about recommendations of site changes that would make temporary hire easier in future?

Can the complete temperature control hire package be provided if required? This could include a combination of liquid chillers, dry air coolers, air handling units, boilers, heat rejection, IDF heaters and temporary pipework, cables, distribution and generators.

Companies now provide everything from a small package of less than 10kW to units of more than 1MW or, in Carrier’s case, a huge 1200kW, which is the largest individual unit available to hire in Europe. It can be used in combination for larger capacities, with pipework, manifold and pump packages also supplied.

Original print headline - How to choose the right AC hire firm