By Sumit Kumar, Embassy Services Private Limited.
Executive Summary: Energy saving is an essential key performance indicator for every commercial building specially where major part of energy is consumed by HVAC system. To maintain ideal IKW/TR rating of the chiller the condenser & condensate system plays major role.During operations of HVAC system, the energy rating is majorly affected by approach temperature across condenser. Regular approach temperature can only be maintained withhigh quality of water parametersused in condensate system with the support of latest water management & treatment techniques. One such technology called as Nalco’s 3D TRASAR system provides a 24*7 dosage of scale inhibitor based on active polymer level by using fluorescence technology. As declared by different chiller manufacturers every 01 degree increases in condenser water approach will increase energy consumption by 3%. Keeping this is mind, the right selection of chemistry with automatic 24*7 dosage Nalco’s 3D TRASAR has been installed after complete study of water parameters and system requirements for water & energy conservation. The system successfully maintainedcondenser approach temperature by 2 degrees throughout the year. During the analysis for a period of one year post installation of Nalco’s 3D TRASAR, it was observed that the condenser approach value was constant & below 2 degreeswith approx. + 0.5 deg C variation during operations. Case Study: Before July 2019, one of the ESPL prestigious site at Noida- had tremendous challenges to maintaining its chiller plant asset due to serious corrosion& erosion in the HVAC pipelines and the chiller condenser tubes. Thecorrosion & erosion was caused due to poor ground water quality at Noida region with presence of high amount of TDS& Chloride salt. This led to regular higher approach values of the condenser tubes in multiple numbers of chiller plants cross the site.Frequent condenser tube cleaning which leads to copper tube deterioration was a major challenge to maintain the operations capabilities of HVAC system. During regular operations the water quality parameters also tends to increase drastically due to which the Chiller tonnage capacity was also reduced as due to sudden increase in the condenser approach significantly decrease in refrigeration capacity. Nalco system was introduced for condensate water management for chiller operationsfrom July 2019. A pre-survey of the system was conducted and following concerned were recognized jointly as primary focus for improvement 8 Very high approach temperatures due to scaling 8 Frequent cleanings 8 Line Punctures due to corrosion & erosion 8 Frequent flushing of water of condensate system. 8 To reduce time for condensate system In addition to above an overall improvement in cooling water management in terms of performance, safety, program administration and communications remains key objective of Nalco 3 DTRASAR cooling water program Below are the parameters used for the comparison as before &after the chemical program implementation. 8 pH – pH measures the relative acidity of the water. The control and measurement of pH are the keys to a successful cooling water program. Significant improvement in pH control by the 3D TRASAR program 8 Conductivity – Conductivity is a measure of free ions in the water. The control of conductivity within a predefined limit is important to the success of cor¬rosion and scale control in a cooling water program. Significant improvement in Conductivity control by the 3D TRASAR program 8 Mild Steel Corrosion Control – Average Mild Steel Corrosion Rate reduced 8 Cu Corrosion Control – Average Cu Corrosion Rate reduced 8 Real Time data monitoring and auto generated alarm & reports receiving Challenges: Before July 2019, one of the ESPL prestigious site at Noida had tremendous challenges maintaining its chiller plant asset due to serious corrosion in the HVAC pipelines and the chiller condenser tubes. This problem was caused due to the ground water quality of Noida region is very poor due to presence of high amount of TDS. This led to higher approach values of the condenser tubes. There was a need of frequent tube cleaning which in turn lead to copper tube deterioration also exceeding the recommended water quality standard etc. Chiller tonnage capacity was also reduced as due to increase in the condenser approach significantly decreased refrigeration capacity. Solution: IncludingNalco multiples suppliers were invited to support the site engineering team in evaluatingits current water treatment program. A Mechanical, Operational and Chemical (MOC) survey of the cooling water system was conducted, because of MOC with all the supplier the implementation of its state-of-the-art 3D TRASAR based program has been finalized. The program includes PSO chemistry, non-oxidizing and oxidizing biocide and a bio-reporter. The 3D TRASAR system incorporates chemistry, algorithms, hardware, and software, which perform together to provide optimal control of a cooling water system. It detects stressful conditions within the cooling systems which cancreate upsets by forming scale, corrosion and microbio related problems and delivers appropriate responses every 5 seconds on a real-time basis. This ensures a more efficient andsafe cooling water system with minimal maintenance, and increased control over key parameters.
Results and Environmental Benefits or Health & Safety Benefits: Energy &CO2 Emission reduction: After implementation of the Nalco 3 DTRASAR cooling water program the system performance has improved significantly. The rise in approach temperatures has reduced drastically & significantly for a similar length of operation which has resulted in an energy savings of approximately 101199 kWh in 8 months. Alternatively,the CO2 emission reduce due to the efficient operation of chiller plant approx.82983 kg has been reduced in the same month of operation (Refer to the below table). Month Energy Saving (kWh) CO2 Emission reduction (kg) Cost Reduction (INR) Aug-19 22629.0 18555.8 219307.9 Sep-19 33191.0 27216.6 330914.6 Oct-19 13833.2 11343.2 144824.7 Nov-19 5268.7 4320.3 55038.4 Dec-19 20530.0 16834.6 221023.0 Jan-20 1169.0 958.6 12545.3 Feb-20 3113.1 2552.7 31230.3 Mar-20 1464.6 1201.0 14632.4 Total 101199 82983 1029517 Equipment Protection: 8 Condenser Tube Corrosion Rates reduced 8 Pipeline erosion Rates reduced 8 Condenser Tubes Repair & maintenance reduced 8 Life of condensate piping system improved. 8 Down time for chillers is negligible due to condensate system 8 Hazardous chemistry & safety: 8 Condenser tube descaling has been reduced, with the aim of the requirement of acidic chemical is reduced. 8 Operators’ health & safety: 8 Due to auto-dosing system physical contact between operators and chemical is negligible. Conclusion: Due to implementation of The Nalco 3D TRASAR cooling water technology below mentioned results are observed: – 8 The health and hygiene of chillers got improved. 8 Provided operational support with overcoming from water treatment problems of condensate system. 8 Very positive results observed inreduction of operation cost. 8 Reduction in equipment breakdown and improvement in down time of chillers especially due to condensate system. 8 Improvement inHVAC efficiency and overall sustainability profile. 8 Water conservation by avoiding irregular blow downs & Cooling tower basin cleaning etc. 8 Energy conservation by maintaining OEM recommended & constant condenser approach. 8 Health and environmental benefits.
