We recently spoke with Sandeep Kumar, president and CEO of Microstaq. The company was founded in 2000 to commercialize MEMS based valve components for industrial, residential, commercial, medical, and transportation applications, an overall $5 billion market, with an average price of $25 per component.
Utilizing a combination of its own and licensed technology, Microstaq has developed a silicon control valve based on MEMS processes to produce three-dimensional mechanical devices in silicon where fluids pass through and are controlled by the micromachined silicon features.
Compared to incumbent mechanical flow-control devices used, for example, in a heating, ventilation, air conditioning and refrigeration (HVAC/R) applications, Microstaq’s valves can be as much as 30% smaller and 35% lighter in weight while improving system efficiency by 10-15%.
MEMS Investor Journal: When we talk about “flow control” what types of media are being controlled?
Sandeep Kumar: Microstaq silicon MEMS actuators are capable of controlling almost any media such as air, oxygen, gaseous and liquid refrigerants; also hydraulic, brake and medical fluids. Today we are applying them in HVAC/R and automotive applications where the mass flow rates approach 1500 pounds per hour and pressures approach 1500 psi.
MEMS Investor Journal: What is the overall size of the flow control market that you are addressing in terms of dollars?
Sandeep Kumar: The overall flow control market is huge and within it the market size for flow control actuators in Microstaq target applications is more than $5 billion. It is comprised primarily of heating, ventilation, air conditioning and refrigeration (HVAC/R), automotive and medical applications.
MEMS Investor Journal: Within these markets where will Microstaq be making its initial sales?
Sandeep Kumar: Our initial efforts are focused on HVAC/R applications including expansion valves for ducted and split systems, chillers, heat pumps, refrigeration systems; and valves for compressor modulation. We will start volume production shipments in Q3 2009.
MEMS Investor Journal: What other types of systems or methods are commonly used to control flow in HVAC/R applications? What are their advantages and disadvantages?
Sandeep Kumar: In HVAC/R applications, the most popular expansion valve technologies used are capillary tube (fixed orifice), thermostatic expansion valves (TXV) and step motor expansion valves (EXV). Microstaq is the only company offering silicon based MEMS valves as an expansion device. The table below describes the features of these four valve technologies.
MEMS Investor Journal: Who are the other players in the HVAC/R market and what is their market share?
Sandeep Kumar: The following table shows major players in the HVAC/R expansion valve market along with their approximate market shares:
Danfoss, Parker and Emerson are mainly serving the thermostatic expansion valve applications. Saginomiya and Fuji-Koki are the leaders of step motor expansion valves. All these players offer capillary tube designs.
MEMS Investor Journal: What led Microstaq to apply MEMS technology to flow control in HVAC/R?
Sandeep Kumar: Global focus on energy conservation and ozone reduction has put the spotlight on HVAC/R, which is the biggest single energy usage and largest ozone depletion segment. HVAC/R systems with higher energy efficiency and no CFCs (chlorofluorocarbons) are now mandated by almost every government and at the same time the consumer is expecting better comfort in cooling and heating.
OEMs in these markets are responding by redesigning their products to replace CFCs with R410A and reduce energy consumption. Microstaq’s MEMS valves are compatible with R410A and reduce energy consumption by permitting circuit-by-circuit control of the refrigerant level in the heat exchangers.
To explain further, current mechanical expansion control requires a large evaporator superheat range, which significantly lowers the heat exchange efficiency of the evaporator. Relatively small changes in ambient conditions can cause the evaporator to deviate from its designed performance range, which translates directly to much higher energy usage. By combining the digital controls and intelligence inherent to semiconductor-based technology, our valves dynamically respond to rapidly changing system conditions by precisely metering refrigerant into the evaporator. This reduces energy usage by 10 – 15% while simplifying AC and refrigeration system design.
MEMS Investor Journal: How does Microstaq MEMS technology work compared with conventional methods for flow control in HVAC/R market?
Sandeep Kumar: Both our valves and conventional methods control refrigerant to the evaporator as shown in the following diagram.
The SEV and the SHC (super-heat controller) together provide an intelligent closed loop control system that is able to maintain the super-heat temperature to a level of control not possible with the capillary tube, the TXV or conventional solenoid valves. The more accurate control results from designing/manufacturing the SEV using MEMS technology. The MEMS based SEV has a much faster response time, much more granular steps, a very accurate tolerance for each step and no shift in performance over time/cycling.
MEMS Investor Journal: What other companies, if any, are applying MEMS to flow control and how does their technology differ from yours?
Sandeep Kumar: Several researchers are working on MEMS valves, however Microstaq is the only company today that has the technology for expansion valves based on MEMS for HVAC/R and has successfully commercialized it for volume production.
MEMS Investor Journal: What design challenges did you have to overcome in bringing your products to market and how did you overcome them?
Sandeep Kumar: The design challenges can be put into two categories. The first relates to the silicon MEMS valve, where we had to devise ways to control sub-micron clearance between the three silicon layers while aligning and bonding them. For this category, silicon surface preparation and proper fixturing play a critical role. Soldering the silicon MEMS to metal substrates was the packaging challenge. Here, proper attention had to be given to inter metallic chemistry between the metallization layer of the silicon and the substrate.
MEMS Investor Journal: How is your solution being received in the HVAC/R market?
Sandeep Kumar: In the HVAC/R market, Microstaq has been working with the leading OEMs in the US and Asia to bring this technology to market. All the major players in air conditioning in the US have tested this MEMS valve technology and the response has been very positive.
MEMS Investor Journal: Who makes the buying decision for your products?
Sandeep Kumar: The buying decision for our products resides in several departments. The first gate is in the engineering group that needs to bless the technology. Other groups can also be very influential, especially upper management and the supply chain.
MEMS Investor Journal: What are the main advantages of your MEMS-based valves in the HVAC/R market?
Sandeep Kumar: Flow-control system customers actively seek solutions that offer improved control functionality, system cost savings and performance enhancement. Our solution addresses these concerns in several ways.
* Energy Savings. The SEV integrated with an electronic control can increase the efficiency of the controlled system and, as noted earlier, reduce its energy consumption by 10-15%.
* Improved reliability. A comparably performing stepper motor valve has at least 5 moving parts compared to our valves that have two moving parts. The actuator piece of our valves is 100% silicon and therefore does not have tensile stress fatigue characteristics found in other typical valve materials. For example, conventional solenoids are specified between 100K and 1M cycles and require frequent re-calibration due to the drift in performance with cycling. In contrast we have tested our valves to over 10M cycles with no change in performance.
* True proportional control. The resistive load characteristic of our valves allows for true linear response compared to non-linear inductive load devices. Linear response makes the control circuitry easier to implement and the behavior is more predictive. An inductive load has a non-linear behavior that is more complex to manage algorithmically.
* Size and weight improvements. Our valves are currently 30% smaller and 30% lighter than a comparably performing valve, which is especially important for automotive systems, although not as critical in HVAC applications.
* Greater system integration. Our valves are implemented in the compact MEMS technology and facilitate component integration (sensors and control electronics) into modular, “plug-and-play” systems and sub-systems for controlling refrigerants.
MEMS Investor Journal: What are your distribution channels? How do your products make their way to the final installation?
Sandeep Kumar: In the HVAC/R market Microstaq sells directly to large OEMs in the US and uses distribution partners in Asia. For the aftermarket, Microstaq will initially rely on OEM aftermarket services and later establish independent distributors.
MEMS Investor Journal: What are your price points? That is, what will end users pay for a Microstaq valve system and how does this compare with conventional systems?
Sandeep Kumar: Microstaq’s valves are priced very competitively with stepper motor valves. For example, in a commercial refrigeration unit, the Microstaq solution is lower in price for an electronic flow control device on an applied cost basis while at the same time offering substantial improvements in performance.
MEMS Investor Journal: Since the initial feedback from OEMs has been positive, what are the obstacles on the sales and marketing front?
Sandeep Kumar: Since a MEMS based valve is new technology in the addressed markets, the main obstacle on the marketing front is building a recognized brand name. On the sales front, the main challenge is to capture the deserved value offered by this new technology.
MEMS Investor Journal: What are the characteristics of a MEMS solution that would lead to it not being selected? What are some applications where it will not be the best solution?
Sandeep Kumar: In general, MEMS solutions are focused at very low flow rates such as with microfluidic applications. Microstaq’s MEMS technology has expanded the usage space to a broad range of fluid control applications. That said there is a segment of the market such as large valves used in oil fields and large petrochemical processing and power generating station applications that will never be replaced with a MEMS valve.
MEMS Investor Journal: What do you see are future applications? Where is your technology going?
Sandeep Kumar: Microstaq’s MEMS valves allow for the integration of electronic control. In the case of expansion valves, they also allow for flow control circuit by circuit. We do see that in the near future integrated smart valves will penetrate the HVAC/R market and will become the norm in this market. Longer term, we will be addressing automotive, medical device and other applications where MEMS valves will offer the substantial advantages we’ve described.
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Sandeep Kumar is a semiconductor industry veteran. In a career spanning more than 20 years he has started and led several companies including Ambrado (integrated multimedia solutions for HDTV & IPTV markets), Anthron (robotic software for entertainment and service robots), and Adimos (wireless multimedia connectivity solutions). His considerable experience spans the areas of leading R& D teams, successfully commercializing emerging technologies, developing new businesses, M&A, forging strategic partnerships, and private equity investments. At TI, his 15-year tenure included responsibilities as General Manager (Cable Broadband Communications), Business Development Manager (Digital Signal Processing Group), and Worldwide Development Manager (Microcontroller Group). Earlier Mr. Kumar was a Venture Partner at Crimson and Executive Advisor to Jerusalem Venture Partners.
Copyright 2009 MEMS Investor Journal
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Posted by: valve actuators | April 29, 2009 at 12:09 AM