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GEA's Global HVAC Technology Blog

GEA's Global HVAC Technology Blog covers a range of topics including:

  • Core HVAC Technologies
  • Technology & Patent Evaluation
  • Manufacturing Technologies
  • Product Quality Improvement
  • Materials/Failures/Corrosion
  • Product/Technology Commercialization
  • Business Strategy Development
  • New Factory Design & Equipment

We'll draw upon our range of experts to provide comments, insights, technical articles and a little humor from time to time

We encourage your participation and feedback!

Manufactuers Optimistic- But Skilled Workers....?

Posted January 14, 2015 4:21 PM by larhere

North American manufacturers are optimistic according to a recent survey of nearly 500 manufacturers by ThomasNet. For the third consecutive year business is trending upwards. The traditionally conservative manufacturing industry is embracing new technologies and strategies, however some concerns are emerging.

Manufacturers See Growth

Manufacturers reported business growth in 2013 with 63% of respondents experiencing further increases in 2014. Manufacturers continue to expand aggressively in core markets, and are investing in capital equipment, production capacity, optimizing manufacturing operations and upgrading facilities. Many view domestic re-shoring as an important growth opportunity. And increasingly, manufacturers are looking globally for business growth with 76% of reporting companies citing some form of overseas business as part of their growth strategy.

Manufacturing Evolution

Manufacturers are embracing new technologies. Interestingly, manufacturers' websites were cited by 56% of respondents as the top tactic to secure new business.

Five key areas were cited as having significant impact on their plans.

  • Sustainable and Green Technologies
  • Advanced Materials
  • Design and Manufacturing Software
  • Automation and Robotics
  • Recycling and Re-manufacturing

Additive Manufacturing/3D Printing was notably further down the list.

The Elephant in the Room

Manufacturing is dominated by Baby Boomers with over 80% of survey respondents over 45 and half of those over 55. As manufacturing moves into the digital/internet age new skills are required however the Milleniums are showing little interest in what is being perceived as a "blue collar" manufacturing industry.

"At a time when the American manufacturing sector is poised for a comeback, the talent shortage is the elephant in the room that could impede progress. It will take a conceerted effort (to) bring in people who are critical to industry's continued success."

- Marc Holst-Knutson - President, ThomasNet

Read the full Report at Thomasnet Survey Shows Business Trending Up for Manufacturers

Editor's Note: CR4 would like to thank Larry Butz, President, GEA Consulting Associate, for contributing this blog entry, which originally appeared here.

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Water Chiller Performance Calulations-Basic Cycle

Posted December 10, 2014 1:00 AM by larhere

Water chillers are commonly employed to chill water for air conditioning systems. This chilled water is circulated thru cooling coils. Air is passed over the coils to be cooled and dehumidified for indoor comfort. The basic components of a water chiller are a compressor and motor, an evaporator, a condenser and assorted piping and controls. In this article we will describe the performance calculations for the basic water chiller thermodynamic cycle.

As an example for our discussion, we will use a compressor with R134a, a flooded evaporator (refrigerant on the shell side) and a shell & tube water cooled condenser also with refrigerant on the shell side. For simplicity of illustration we will assume an 85% efficient centrifugal compressor and no pressure drop in suction or discharge piping. Chilled water enters the evaporator at 54 oF and leaves at 44 oF. Cooling water enters the condenser at 85 oF and leaves at 95 oF.

The evaporation is a constant pressure process and the evaporator saturation pressure must be at a temperature colder than the leaving chilled water temperature for the heat transfer to occur. The refrigerant leaves the evaporator shell as a saturated vapor and enters the compressor.

The compressor supplies work to raise the refrigerant to the condenser saturation pressure. The condenser saturation pressure must be higher than the leaving condenser water temperature for heat transfer to occur. The compressor work required is the product of the refrigerant mass flow times the vapor enthalpy at the entrance to the condenser minus the vapor enthalpy leaving the evaporator.

The heat rejected in the condenser is the sum of the heat transferred in the evaporator plus the work input of the compressor. The condensed refrigerant leaves at the condenser saturation pressure, passes thru an expansion device that reduces the pressure to evaporator pressure, and enters the evaporator. In the expansion process, some of the liquid flashes to gas and the refrigerant entering the evaporator is a two phase mixture.

The chilled water is cooled in the evaporator by evaporating the refrigerant. The evaporator heat transfer capacity is equal to the building load. The refrigerant mass flow that must be delivered by the compressor is equal to the building load divided by the difference in enthalpy of the entering and leaving refrigerant conditions.

In the basic cycle, the liquid refrigerant leaves the condenser at its saturation temperature.

The refrigerant properties at various points in the cycle are:

Condenser Saturation Temperature, Tsat=97 oF

Evaporator Saturation Temperature, Tsat=42 oF

Enthalpy leaving Evaporator, hg=172.9 Btu/lbm (saturated vapor @ 42 oF )

Enthalpy leaving Condenser, hf=107.8 Btu/lbm (saturated liquid @ 97 oF )

Entropy entering Compressor, sg=0.412 Btu/lbm-R (saturated vapor @ 42 oF )

Enthalpy leaving Compressor, hg=181.3 Btu/lbm (ideal isentropic compression)

Isentropic enthalpy rise due to compression, ∆hcomp=181.3-172.9=8.4 Btu/lbm

Compressor efficiency, Ƞ=0.85

Enthalpy leaving Compressor hg=172.9+8.4/0.85=182.8 Btu/lbm

From these values several performance parameters of the cycle may be calculated on a per ton basis.

Capacity=12000 Btu/h-ton

Evaporator enthalpy rise=172.9-107.8=65.1 Btu/lbm

Refrigerant mass flow rate=12000/65.1=184.5 lbm/h-ton

Compressor work=184.5*8.4/0.85=1824 Btu/h-ton

= (1824 Btu/h-ton)/(3412 KW-h/BTU)=0.535KW/Ton

In future blogs we will discuss the performance improvements of subcoolers and economizers.

See other blog posts by Jim Larson

Water Side Pressure Drop in Shell and Tube Heat Exchangers

Designing Water Cooled Condenser Tube Bundles

Designing Flooded Evaporator Shell & Tube HXRs

Editor's Note: CR4 would like to thank Jin Larson, GEA Consulting Associate, for contributing this blog entry, which originally appeared here.

3 comments; last comment on 12/13/2014
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Conquering Information Overload

Posted November 19, 2014 1:00 AM by larhere

Who isn't battling Information Overload?

According to Daniel Levitin, McGill University psychology professor " Americans took in five times as much information every day in 2011 as they did in 1986". In 1976 the average grocery store had 9,000 products, today its 40,000 products. All of this is more than the brain is configured to handle.

Levitin says there are steps we can take to reduce Information Overload. I've condensed his 10 steps to the 5 most important ones. (Read all ten, and the full article "Ten Steps to Conquering Information Overload" authored by Laura Shin.)

1. Don't Multi-task - Switching between taks will actually make you feel exhausted, disoriented and anxious says Levitin.

2. Take Breaks - "People who take a 15-minute break every couple of hours are much more efficient in the long run".

3. Delegate - Push down authority and empower people under them to exercise their good judgment.

4. Daydream - the daydreaming mode acts as a neural reset button and replenishes some of the glucose you use up in staying on a task.

5. Do Toughest Tasks in the Morning - "Important decisions should be made at the beginning of the day, when gumption and glucose is highest".

Read More

Editor's Note: CR4 would like to thank Larry Butz, President, GEA Consulting Associate, for contributing this blog entry, which originally appeared here.

3 comments; last comment on 11/20/2014
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Corrosion Analysis: Understanding the Equipment

Posted November 05, 2014 1:00 AM by larhere

Back again. Today we'll discuss the third step in the corrosion evaluation/mitigation process

1. Identify the corrosion mechanism.

2. Understand the environment, both external and internal.

3. Understand the equipment - materials of construction, operating cycles, hours.....

4. Identify alternatives - materials, coatings, limiting operating envelope, changing the environment (water treatment, alternative lubricants/refrigerants, filter the air, etc.), redesign the machine (better drainage, eliminate contact of dissimilar metals, .....)

5. Implement change.

6. Monitor results.

3. Understand the equipment - materials of construction, operating cycles, hours…..

In the previous post in this series we discussed how important understanding the operating environment is when working to solve a corrosion problem, not surprisingly, it is just as important to understand the equipment which operates in that environment.

One of the challenges for a failure analyst working with a client to solve a corrosion problem is thoroughly understanding the equipment that is failing - what are the materials of construction, how are the materials processed, why were the materials selected, is there more than one supplier of materials or components, what is the typical duty cycle for the equipment, what are the extremes of the operating map, etc., etc., etc.?

A lot of these questions can be answered by reviewing engineering drawings and documentation, but much of this information is only available via the tribal knowledge of the people who work with, or on the equipment every day. Thus, it is crucial for design, manufacturing, service and purchasing personnel to share their tribal knowledge regarding how and why the equipment is designed and built the way it is with whomever is charged with analyzing the corrosion problem. Again, just like understanding the environment, the better we understand the equipment, the better and more robust and more economical will be the solutions that are found to address the corrosion problem.

Editor's Note: CR4 would like to thank PJ Sikorsky, GEA Consulting Associate, for contributing this blog entry, which originally appeared here.

6 comments; last comment on 11/12/2014
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Reshoring Gains Momentum

Posted October 29, 2014 8:50 AM by larhere

Earlier this month we highlighted a BCG study ("The Shifting Economics of Global Manufacturing") showing the dramatic changes in manufacturing competitiveness in the leading 25 countries.

BCG has followed this study up with a survey eliciting responses from 252 senior level US based manufacturing executives. Results were compared to a similar survey one year ago in August 2013. The summary report ("Made in America, Again") consist of 13 slides which can be viewed at the BCG Website.

(Note: This study is of manufacturing capacity serving the US market)

Most noteworthy findings include:

  • 54% of respondents are considering bringing production back to the US
  • US based executives believe that a larger share of their manufacturing base will be US based five years from now.

  • The US has surpassed both China and Mexico as the most likely destination for new capacity to serve the US market.

  • Access to US skilled labor is a major factor in reshoring.
  • Three times as many executives believe there will be net manufacturing job growth (vs. loss) over the next 5 years.

Read the Summary Report slide presentation here.

Editor's Note: CR4 would like to thank Larry Butz, President, GEA Consulting Associate, for contributing this blog entry, which originally appeared here.

3 comments; last comment on 10/31/2014
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Trane Introduces HFO1233zd in Series E Centrifugal Chillers

Posted October 22, 2014 9:23 AM by larhere

Trane introduced the first chiller using R1233zd at the Chillventa Expo last week in Italy. Air conditioning manufacturers are scrambling to comply with the revised EU F-gas Regulation going into effect 1/1/2015 limiting and banning "F Gases" in the EU.

HFO 1233zd is described as a single component refrigerant, both low toxicity and non-flammable. It was originally developed for use as a blowing agent but has also been found to be a high efficiency alternative to R123. It has been submitted for ASHRAE designation and classification and is expected to be classified as A1. Its GWP is low, listed under the F-gas regulations as 4.5 but variously described as 6, by UNEP, or 1, by Honeywell.

According to the announcement...

The Trane Series E CenTraVac is a large-capacity chiller (capacities from 2600kW to 14,000kW) for applications like comfort cooling of large commercial buildings including district cooling. It is available in Europe, the Middle East and other 50Hz markets, and received Air-Conditioning, Heating and Refrigeration Institute (AHRI) Certification.

Honeywell markets the new refrigerant under the tradename Solstice zd, a US SNAP-approved alternative to R123 and 245fa. It has a GWP of 1. It will have applications in large centrifugal chillers, organic Rankine cycles and high temperature heat pumps.

Also Read:

U.S. EPA Moves to Phase-out Familiar HFCs

Editor's Note: CR4 would like to thank Larry Butz, President, GEA Consulting Associate, for contributing this blog entry, which originally appeared here.

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