ACTA is working on developing new products in two main areas:

 

 

The next generation of refrigerants with improved heat transfer and reduced energy consumption.

 

  • Nanoparticles added to fluids have been shown to increase the heat transfer of water, ethylene glycol, and engine lubricating oils. ACTA Technology's research expanded this earlier work to include adding nanoparticles to fluorinated liquids that are being used as refrigerants in vapor compression systems.
  • ACTA Technology developed a stable, long-lasting nano solution that substantially increased the thermal conductivity of the nano-refrigerant. This new process resulted in a 192% improvement in thermal conductivity with only 1.3 % of the nanoparticles being added (wt. %). This new nano-refrigerant has the capability to improve the heat transfer in the system; thereby improving the energy efficiency of a typical vapor compression system.

Ground Source Heat Pumps

ACTA developed and patented new nanofluids for ground source heat pumps through a research contract from the US Environmental Protection Agency (EPA).

Summary of our research work:
We were able to develop nanofluids that were stable, have improved heat transfer properties and have lower life cycle cost than the existing glycols used in Ground Source Heat Pumps (GHPs).
Test Apparatus
In order to simulate the ground source loop two well insulated tanks were used. One tank was the cold tank that simulated the ground or pond type (GHPs). A chiller and ice was used to maintain the cold temperature. Tank heaters were used in the hot tank. The hot tank simulated the condenser of a GHP. A flow meter recorded the flow rates and a data acquisition system monitored five K type thermocouples. A ground source heat pump (GHP) uses a cooling loop to exchange heat with the ground or pond. During the winter months, the system absorbs energy from the earth and during the summer months the system rejects energy to the earth. A pond type GHP uses a loop that is below the water level. The pond provides a nearly constant isothermal heat sink for the system. The entering temperature for the ground source loop fluid is 80 to 85oF (28oC) inlet and 55 - 58oF (12.8oC) outlet. The temperature of the earth is relatively stable throughout the year.

 

The figure above illustrates that ACTA was able to develop nanofluids that have better heat transfer properties in an actual moving system that simulates a GHP. The Propylene glycol nanofluids were better heat transfer fluids than water. We substantially improved the heat transfer of propylene glycol and water mixture by 48%. The potential energy savings is very significant.

TiO2 Nanofluid

ACTA Technology is developing a new micro-fluidic pump that uses titania (TiO2) nanoparticles, propylene glycol water mixture, ultra-violet (UV) energy, and novel parallel plate device. This new micro-fluidic device is a modification of a nano-rheometer first developed by NIST researchers. The micro-fluidic device has a parallel plate that moves without any detectable crosstalk and angular deviation making it an excellent candidate for micro-fluidic pumping.
Photocatalytic of titania is well known and other researchers have demonstrated that titania can be used for disinfection, detoxication of water and waste water, air purification, anti-fogging surfaces, self cleaning surfaces, self sterilization, amongst other applications.
Another amazing characteristic of titania nanoparticles which was recently discovered is its superhydrophilicity when exposed to UV light (2005). UV light causes the contact angle to decrease with time and finally reaches almost zero. Other researchers have shown that the critical heat flux also increases. It is this change in contact angle that enables the pumping action.

 ACTA observed that the titania propylene glycol nanofluid behavior like a superhdrophilic surface. The boiling point and maximum heat flux are changed. 

Video of TiO2 Nanofluid.


New nano-Micro-Electrical Mechanical Systems (MEMS) devices

 

  • ACTA Technology has licensed a nano-positioner technology from NIST and co-invented a new MEMS device in collaboration with NIST researcher, Dr. Nick Dagalakis. 
  • ACTA Technology is using this novel nano-MEMS device first developed by NIST for mass sensing. The device can also be used as a micro-rheometer, blood clotting meter and nano-positioner for focusing mirrors or for building other MEMS devices.
  • NIST's VIDEO OF THE NANOPOSITIONER

 

 Blood Clotting Device

 Warfarin® is a powerful anticoagulant initially used to kill rats by causing uncontrollable internal hemorrhaging. Today 30 million Americans are taking Warfarin to prevent blood clots, heart attacks, deep vein thrombosis, and stroke; with 2 million new patients starting the drug per year. Warfarin is known under the brand names Coumadin ®, Jantoven ® , Marevan ® , Lawarin ®, Waran ®, and Warfant ®.

Unfortunately, the therapeutic range for these of type of drugs is very narrow and is sensitive to several factors that change throughout the day like diet, other medications, and exercise. In fact, Warfarin is one of the top three drugs leading to emergency department visits by the elderly, accounting for 17.3% of such visits. Presently, Warfarin is dosed by a trial-and-error method. Patients are initially given a fixed 5mg starting dose. On each subsequent visit to their doctor's office, the International Normalized Ratio (INR) test is used to measure clotting time, and the Warfarin dose is gradually adjusted using the INR test until a stable dose is achieved. This usually occurs when the INR value is between 2.0 and 3.0. But clinical factors, such as height, weight, age, race, diet, activity level, use of amiodarone, and use of other drugs known to induce the metabolizing enzyme CYP2C9 all affect the final therapeutic dose which can vary throughout a patient's day. Foods high in vitamin K will also affect blood viscosity and INR reading. Because of these variables, it is difficult to achieve stable INR readings in some patients. Hence, there is a need to have a portable, low cost medical device for point of care and home use for measuring blood clotting time (INR).
ACTA is developing a commercially viable hand held point of care and home use device to determine changes in blood clotting rates by using a drop of the patient’s whole blood taken by a finger prick. This new medical device uses a novel suspended plate MEMS (Micro Electro Mechanical Systems) design that was co-invented by NIST (National Institute of Standards and Technology) and ACTA researchers in 2012 under a cooperative research and development agreement (CRADA).  Link to video by ACTA of the MEMS Device for Blood Clotting.

 

 Energy Harvesting

ACTA is working on the next generation of energy harvesting devices.  Dr. Yang is an expert in building three deminsional, six degree of freedom MEMS devices  Present day devices harvest energy but their efficiencies are very low because the wave energy must be normal to the device.  The hexapod was first developed by Dr. Dagalakis at NIST.  Dr. Yang worked with Dr. Dagalakis and became the first person to build the 3 D, 6 degrees of freedom device. ACTA believes a new design will imcrease the erngery conversion rate.  The proper orientation will harvest the highest amount of energy. ACTA is working on building this  new device.   Link to video of the Hexapod from NIST.