PayBackTime is a multi-platform compatible simple perl/CGI interest loan calculator, similar to `VeryInteresting` and `AffordaBilly` but focused on determining how long it will take to pay off a loan or credit card, given a minimum payment, balance, and interest rate. The results will show the time it will take to pay off the balance with that monthly payment, number of payments, and the total interest the user will end up paying.
The Fluid Flow Calculator is a multi-platform compatible calculator that is used to calculate pipe friction losses for straight piping handling water and water with varying percentages of ethylene glycol. The calculator uses an algorithm developed from the basic principles of fluid mechanics. The program is based on the Darcy-Weisbach equation, the Colebrook equation, and the Moody equation. The program is intended for use only on straight piping. The program does not include pressure losses due to elevation differences, or flow through fittings.
The Engineering Units Conversion Calculator is a multi-platform compatible program that allows users to convert units such as: Energy, Pressure, Volume, Density, Specific Volume, Specific Heat (Entropy), Enthalpy, Viscosity (absolute), and Coefficient of Heat Transfer.
The Engineering Economics Calculator is a multi-platform compatible program that allows users to input a loan amount, an interest rate, and the number of years of the loan. The program then outputs the monthly mortgage or loan payment. The program uses the single payment compound amount equation. Version 2.0 will include the single payment present worth equation, the sinking fund factor, the capital recovery factor, the uniform series compound amount factor, and the uniform series present worth factor.
The Psychrometric Calculator is a multi-platform compatible calculator that is used to compute the thermodynamic properties of moist air. These properties are used by mechanical engineers to design Heating Ventilating & Air Conditioning (HVAC) systems and processes. The program uses equations which are derived from the perfect gas relations and is suitable for most HVAC engineering applications - within the range of -40 to 150 degrees fahrenheit. Specifically, the program is based on the procedure outlined in the 1997 ASHRAE Fundamentals Handbook, Chapter 6 - Psychrometrics, section: Numerical Calculation of Moist Air Properties. The program also uses data (absolute pressures vs temperature for water at saturation) from Table 3 (Thermodynamic Properties of Water at Saturation), also from chapter 6 of the 1997 ASHRAE Fundamentals Handbook.
