ACHRNEWS

The Contractor’s Investigative Tool

February 6, 2003
Onset Computer Corporation has been designing and manufacturing dataloggers for over 20 years. Everyone from NASA astronauts to archaeologists have used the company’s data recording tools, but the company says that the heating and air conditioning industry can get the most uses and benefits out of them.

Joanna Phillips, product marketing manager for Onset, explained that the company’s HOBO dataloggers offer hundreds of possibilities. The hand-held, battery-operated monitors can be equipped with numerous sensors to read a variety of indoor conditions.

The datalogger can be left within the building space over a period of time to record and log environmental conditions. This can include the fluctuations in temperature and changes in humidity. She said that the dataloggers can also record how often lights in a building are turned on and off.

According to Phillips, contractors will get the most use out of the dataloggers because they can help diagnose IAQ problems, assist in troubleshooting and preventive maintenance, and detect conditions that could lead to mold problems. Dataloggers are also beneficial in tracking energy usage and pinpointing areas where customers can save money.

Dataloggers can be used in warehouses where temperature variations occur. (Photo courtesy of Onset Computer Corp.)

Curing Sick Buildings

In the IAQ department, Phillips explains that the dataloggers, when used with an external sensor, can measure carbon dioxide (CO2) and relative humidity (rh) over a certain amount of time. If the dataloggers reveal to the contractor that CO2 levels continue to rise over a given time, there is a good possibility that the building’s ventilation needs to be increased.

According to Onset, the company offers dataloggers that have built-in temperature and rh sensors so that both sets of data can be collected at the same time in the same place. Temperature and rh levels can be taken inside and outside the buildings for comparison. By collecting data from several locations at the same time, contractors can begin to determine which parts of the building provide room for improvement in ventilation and energy savings.

The HOBO dataloggers have also been instrumental in diagnosing “sick building syndrome.”

Daniel Aenine works as a technical consultant in Stockholm, Sweden. He said that dataloggers are an integral part of his work when it comes to uncovering IAQ problems.

According to Onset, buildings in Scandinavia have had problems related to tight construction. Due to frigid temperatures, homes and buildings in the area have been built tight to keep heat in and save energy. While this has been effective solution for saving energy, it has created a new problem. The airtight homes and buildings can be the perfect environment for molds and fungi to grow.

According to Aenine, crawl spaces under homes run the most risk of developing mold growth. Aenine said that mold and fungus can be prevented in crawl spaces if the relative humidity stays below 70 percent. Long-term monitoring of the humidity in the crawl space can help in determining if any precautions should be taken to keep relative humidity low.

To monitor the rh, Aenine uses an Onset HOBO relative humidity/temperature logger. If the logger displays regular rh levels above 70 or 75 percent, Aenine will suggest a dehumidifier to the homeowner.

Onset's HOBO H8 datalogger. (Photo courtesy of Onset Computer Corp.)

Saving Energy

For Gary Dexheimer, dataloggers are an important part of his business. He is the owner of Sentry Energy and it is his responsibility to quantify energy studies for several firms and companies.

Part of Dexheimer’s job is to find out if a company’s HVAC equipment is performing up to its potential and determine if an equipment upgrade could save energy and money.

Dexheimer travels all over the country assisting a number of utilities and companies. Recently, Dexheimer left for Korea to perform energy audits at a military base. He will be using a number of HOBO units to record the run times on the HVACR equipment at the base. After monitoring a number of factors, Dexheimer will be able to present those at the base with his findings and let them know where they can save money and make upgrades.

“We can use dataloggers to see if the system is working up to its potential,” said Dexheimer.

He explained that in some applications, systems are oftentimes oversized. Customers may not know it, but their systems might be wasting energy. The same can be true for undersized equipment.

By monitoring the run times, Dexheimer can determine how much energy the system is using. He can then compare this to the energy output of a newer system, and demonstrate the potential cost savings for the customer. If the customer opts for a new unit, Dexheimer said it is important to log the data again to make sure that these new systems are living up to expectations.

Dexheimer said dataloggers can be an excellent selling tool for contractors. The monitors allow contractors to give concrete numbers to their customers. These numbers can lead the contractor to suggest system improvements to the end user.

Onset also offers software to use with its HOBO dataloggers. The software is called BoxCar Pro, and allows contractors to plug the unit into a PC. The software will download all of the recorded information and organize them in clear charts and graphs. These charts can be printed off and presented to an end user.

“People want to see hard data,” said Dexheimer. “The customer likes to get these reports and look over them.”

He said that the reports can tell the customer where improvements can be made and how a new system can save energy in the future. For example, the contractor can tell the customer the estimated price of a new system. This can then be compared to energy savings over time. Dexheimer said that this is important because most customers will be able to pay for the new system in energy savings over time.

The HOBO LCD temperature/relative humidity datalogger. (Photo courtesy of Onset Computer Corp.)

Troubleshooting, Maintenance

Dexheimer said that dataloggers are also very valuable in troubleshooting and preventive maintenance of HVACR equipment.

For example, he said the dataloggers can be used to perform trend logging. The datalogger can monitor a motor over time. If the unit records that the motor is using more and more energy over time, Dexheimer says it could mean that the motor is going bad.

He also noted that the datalogger can track CO2 from the stack on a boiler. If the logger begins to record an increase in CO2, the system efficiency could be going down.

Onset also suggests some troubleshooting tips with dataloggers.

The loggers can simultaneously record heating and cooling. This can ensure that when the cooling coil valve is open, the heating coil valve is closed.

Contractors can also look for unnecessary equipment operation of chillers, pumps, air handlers, exhaust fans, and other units. The datalogger can monitor the equipment current to find out when a compressor or pump is functioning and how often. This can clue a contractor in to how often a piece of equipment is running.

Phillips says that although the HOBO units have a variety of functions and uses, they can also be used for simple measurements, such as temperature.

Dataloggers can be especially handy in office buildings where there could be several temperature discrepancies. Building managers and contractors can test spaces where occupants have had complaints to prove whether or not the area is getting the adequate heating and cooling from the system.

For more information, visit www.onsetcomp.com.

Publication date: 02/10/2003