• Changes in plant operating conditions
• Better utilization of plant maintenance resources
• Modification to plant equipment (i.e. HiTRAN Thermal Systems)

Energy cost reduction opportunities are often achieved by changes in the process in a non-obvious manner through energy paths. Strong experience using Pinch Technology is crucial to identifying specific energy system characteristic that allow these savings to be achieved.


Performance Monitoring and Targeting

Performance Monitoring and Targeting (M&T) is a disciplined approach to energy management that ensures that energy resources are used to the maximum economic advantage. It has two principal functions:

• The ongoing control of energy use
• Planned improvements in the efficiency of energy use

The benefits of an M&T system have been demonstrated to be between 5% and 25% of the annual site energy bill. Importantly, these savings can be achieved with little or no capital investment and result from improved operating practices, plant adjustments, operator training, and more. In addition to energy cost savings, the systematic investigation of energy use through M&T can lead to improved product quality and yield, reduced maintenance, and reduced or deferred capital expenditure.

It is essential that a management structure exist to make effective use of the information provided by the M&T system. The principal steps of an M&T system are:

• Measure utility consumption levels
• Compare consumption levels against pre-determined standard usage
• Report on variances from standards
• Act on the information received
• Establish long-term targets for "Best Practice" operation
• The typical utilities to which M&T can be applied are: Steam, Primary Fuels, Electricity, Water, Effluent, Process Feedstock, and Product Wastage.

Refrigeration System Audit

Refrigeration systems often operate in an inefficient manner due to faults that are not catastrophic, but that reduce capacity, increase power consumption, or both. This is because refrigeration systems are designed for extreme conditions of climate and load, but operate most of the time well away from this peak. Since most users also have spare capacity, these situations can persist for long periods without being detected.

Veritech recently completed an audit on a three-stage propane refrigeration system with an annual operating cost of $2 million per year. The identified savings opportunities totaled 35% of the annual operating cost. Of the $700,000 per year savings identified, $230,000 resulted from operational modifications requiring little or no capital investment. The remaining savings required some capital investment at a payback of one to two years.

In the study Veritech reviews the refrigeration system as a whole, following several critical steps:

The first step is to examine the cooling loads served by the plant. This review is important, as significant problems that occur are not always concentrated in the refrigeration plant, and a wide study of the plant can reveal useful results. For example, it is possible to reduce the load on the plant by up to 50% by employing simple heat recovery techniques.

The next step is to examine the distribution system for the refrigerant to the individual services. In one plant, the cost of pumping the chilled water was greater than the cost of operating the chiller. Some relatively low-cost modifications can bring these costs to a reasonable level.

Then we turn our attention to the refrigeration plant itself. By analyzing the operating conditions of the plant in relation to the conditions of load and the weather, we can determine if the plant is operating as it should. This is considered at the refrigeration plant level and the particular condition of each refrigeration circuit. There are many faults that can occur and have a large energy cost. These can be fouling of the evaporators and condensers, and malfunction of parts of the equipment. Where these can be identified, appropriate action will be recommended.