RPA Guidelines for the Design And Installation of Radiant Panel Heating and Snow/Ice Melt Systems (2004 Edition). © Copyright 2004, All Rights Reserved.
Development of a Two Dimensional Transient Model of Snow-Melting Systems, and Use of the Model for Analysis of Design Alternatives, ASHRAE 1090-RP, 2001, Spitler, Rees, Xia, Chulliparambil, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. and Oklahoma State
University. Reprinted by permission from ASHRAE. © Copyright 2004, All rights reserved
A Simulation Tool for the Hydronic Bridge Snow Melting System, Liu,Spitler, Submitted to the 12th International Road Weather Conference, Oklahoma State University, School of Mechanical and Aerospace Engineering, © Copyright, All Rights Reserved.
An Analytical Algorithm for Hydronic Circuit Analysis and Assessment of Equipment Performance Kilkis, copy written © 2005, by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc
Snow Melting - Idle/On
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advanced snow melt control would maintain a minimum standby
surface temperature at, or just below, freezing and then
move into the 'on mode' in the presence of snow. In this
manner the time needed to bring the surface temperature
above freezing is significantly shortened allowing the heat
to move into the snow faster, turning it into liquid, and
then evaporating it and/or draining it away to maintain a
clean surface. The same higher end controls can be
programmed to run for a certain amount of time following
snowstorms to ensure that any residual accumulation is
cleared. However, in a mild year with very little snowfall
this strategy could be more expensive to run then the on/off
method. This comparison illustrates that storm
characteristics play a major role in how control strategies
can pass or fail to meet a client’s needs and influence
operating costs. In reality, what a client experiences over
the life expectancy of the system in terms of performance
and efficiency, is determined by the size of their initial
investment in the system and controls.
Click here to see a snow meting piping and control
look at the engineering of snow melt systems to determine what a
control system must manage when asked to perform.
have studied thermal dynamics know that energy cannot be
saved although it makes for an interesting discussion with
those that use the word ‘save’ in marketing initiatives.
Energy cannot be created nor can it be destroyed therefore
it cannot be saved. It is just moved around from one place
(form) to another. What a client pays in exchange for
converting energy from one form to another and the benefits
received in the process are defined by the efficiency of the
conversion. In the case of a fuel-fired boiler used to heat
snow melt fluid, energy in the gas or oil is released to the
liquid through the combustion heat exchange process. Energy
not dispersed into the fluid is radiated, conducted,
evaporated or convected into the boiler room or up the
chimney. The amount of heat required in the antifreeze/water
and the electrical power to move it is a function of several
factors including, but not limited to, tube spacing, depth,
soil conditions, storm characteristics, slab dimension, and
so on. Control systems actually regulate the flow of energy.
We define the energy required at the surface as heat flux.
The steady state heat flux calculation for melting snow is:
qo = qs + qm +
Ar ( qh + qe),
= heat flux required at snow-
melting surface, Btuh/ft2
= sensible heat flux, Btuh/ft2
= latent heat flux, Btuh/ft2
= snow free area ratio,
= convective & radiative heat
flux from snow free surface, Btuh/ft2
= heat flux of evaporation, Btuh x
Click here for part I, Introduction
Click here for part II,
Click here for part III,
Controls & System Performance
Click here for part IV,
Area Free Ratio and Frequency
Click here for part V,
Click here for part VI,
Storm Data and Loads
Image credit: Development of a Two Dimensional Transient Model of Snow-Melting Systems, and Use of the Model for Analysis of Design Alternatives, ASHRAE 1090-RP, 2001, Spitler, Rees, Xia, Chulliparambil, American Society of Heating, Refrigerating and
Air-Conditioning Engineers, Inc. and Oklahoma State University.