U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: David A. Yashar (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 26 - 50 of 51

Condensadores de Tubo con Aletas Optimizacion Mediante Sistema Inteligente

February 1, 2008
Author(s)
Piotr A. Domanski, David A. Yashar
The refrigerant circuitry influences a heat exchanger's attainable capacity. Typically, a design engineer specifies a circuitry and validates it using a simulation model or laboratory test. The circuitry optimization process can be improved by using

Air-Side Velocity Distribution in Finned-Tube Heat Exchangers

December 17, 2007
Author(s)
David A. Yashar, Hong H. Cho
The performance of finned tube heat exchangers is greatly affected by the distribution of the air that passes through it. The air side velocity distribution is largely left unknown because it is difficult to measure accurately. In this study, we examined

Application of an Evolution Program for Refirgerant Circuitry Optimization.

December 7, 2007
Author(s)
Piotr A. Domanski, David A. Yashar
Increased concerns about climate change have emphasized the importance of air-conditioning and refrigeration systems with a high coefficient of performance (COP). The effectiveness of heat exchangers significantly influences the vapor-compression system's

Application of an Evolution Program for Refrigerant Circuitry Optimization

December 7, 2007
Author(s)
Piotr A. Domanski, David A. Yashar
Increased concerns about climate change have emphasized the importance of air-conditioning and refrigeration systems with a high coefficient of performance (COP). The effectiveness of heat exchangers significantly influences the vapor-compression system s

A Microfabricated Flow Controller for Refrigerant Expansion

October 1, 2007
Author(s)
David A. Yashar, Piotr A. Domanski, Don DeVoe
A flow controller for refrigerant expansion is reported. Devices are fabricated using a micromolding technique developed for thick nickel electroplating. The device consists of a short tube restrictor with an integrated normally-open valve which, when

Optimization of Finned-Tube Condensers Using an Intelligent System

May 1, 2007
Author(s)
Piotr A. Domanski, David A. Yashar
The refrigerant circuitry influences a heat exchanger s attainable capacity. Typically, a design engineer specifies a circuitry and validates it using a simulation model or laboratory test. The circuitry optimization process can be improved by using

MEMS Sensors for HVAC&R: Small, Fast, Cheap (in Polish)

August 1, 2006
Author(s)
David A. Yashar, Piotr A. Domanski
Microelectronic mechanical systems (MEMS) have revolutionized the market for sensors by providing small, fast-responding measurement devices at low cost. They have been widely accepted in several common products. As an example, today's automobile uses

MEMS Sensors for HVAC&R: Small, Fast, Cheap.

December 1, 2004
Author(s)
David A. Yashar, Piotr A. Domanski
Microelectronic mechanical systems (MEMS) have revolutionized the market for sensors by providing small, fast-responding measurement devices at lowcost. They have been widely accepted in several commonproducts. As an example, today’s automobile uses

Vibration Signatures for Three Positive Displacement Compressors

December 1, 2004
Author(s)
David A. Yashar, William V. Payne
This report presents vibration data for three positive displacement compressors which will be used to evaluate Microelectromechanical Systems (MEMS) vibration sensors at a later time. The axial, radial and tangential vibration signatures of three

MEMS Sensors for HVAC&R

May 1, 2004
Author(s)
David A. Yashar, Piotr A. Domanski
MicroElectronic Mechanical Systems (MEMS) have revolutionized the market for sensors by providing small, fast-responding measurement devices at very low cost. These measurement devices have been widely accepted in many areas of engineering and have vastly

An Optimized Design of Finned-Tube Evaporators Using the Learnable Evolution Model

April 1, 2004
Author(s)
Piotr A. Domanski, David A. Yashar, Kenneth Kaufman, RK S. Michalski
Optimizing the refrigerant circuitry for a finned-tube evaporator is a daunting task for traditional exhaustive search techniques due to the extremely large number of circuitry possibilities. For this reason, more intelligent search techniques are needed

Energy Consumption Measurements Using AHAM HRF-1 and ISO 8561

March 10, 2003
Author(s)
David A. Yashar
This investigation compares the energy consumption ratings obtained for refrigerators using the Association of Home Appliance Manufacturers (AHAM) HRF-1 test procedure, as adopted by the United States Department of Energy (DOE), and the International

An Investigation of Refrigerant Void Fraction in Horizontal, Microfin Tubes

January 1, 2001
Author(s)
David A. Yashar, M J. Wilson, HM R. Kopke, D M. Graham, J C. Chato, TJD A. Newell
A series of experiments to determine void fraction in both condensation and evaporation have been performed in horizontal microfin tubes with refrigerants R134a and R410A. Mass flux varied from 75 kg/m2-s to 700 kg/m2-s and average test section quality