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Since our inception, Forward Engineers has offered comprehensive Energy Audits to our clients.  While energy audits completed according to ASHRAE guidance are very valuable and informative, we have found that for many of our small business clients the cost for a full audit is simply outside of their budget.  Additionally, many small businesses simply don’t need the same level of detail that a Level 1 audit includes.  Therefore, we are happy to introduce our new auditing service specifically targeting small businesses.

In general, an energy audit is a survey of a commercial building that looks at the envelope (walls, roof, windows), the mechanical systems (heating, air-conditioning), lighting and building controls (thermostats, lighting controls) to find areas in which the building owner can reduce expenses by using less energy.  Our small business audit costs as little $200 and includes a walk through of the facility with a licensed engineer to identify cost savings opportunities.  We’ll take the time to look at each building system with you and discuss options that can save you money.  After the walk through is complete, we’ll follow-up by sending an email detailing our findings.  Additional services such as a review of past energy bills and computer modeling can be easily included, if desired.

Our goal is to provide an affordable service that a business can use to reduce their energy costs.  We are happy to work with you to find a solution that fits your budget.  If you own or manage a building and are interested in an audit, please contact us today.

One of the most interesting phenomena in fluid dynamics (at least to me) is cavitation.  In short, cavitation occurs when bubbles of liquid vapor are formed in a fast moving liquid where the pressure is temporarily reduced.  Think bubbles coming off of a propeller in the water.  Read on to see exactly how this happens and why engineers care about it.

Water is considered an incompressible fluid.  What this means is that you cannot reduce it’s volume by compression (aka density is constant).  Try to squeeze a full water bottle into a smaller shape.  You won’t be able to do it because the water won’t compress.  Now, if you can’t compress it you also can’t expand it in its liquid form.  This means that you can’t take a half full glass of water, put a vacuum pump on it and somehow get the liquid water to fill the entire glass.  You would only move the water around.  with the pressure reduced, you would eventually cause more of the liquid to become a gas but now you have less liquid than you started with.  It’s this last property, conversion of liquid to vapor when the pressure is low, that is the principle cause of cavitation.

Whenever water is travelling fast enough, usually around a propeller, impeller or a section of pipe where flow is constricted, the pressure in small regions can temporarily get below the vapor pressure.  Below this pressure the liquid can phase change to a gas.  When this happens, a cavity filled with liquid vapor is formed which appears as a bubble.  This is cavitation.  The danger of cavitation comes when the pressure returns to normal and the cavity collapses.  This can generate a shockwave capable of damaging metal over time.  Because of this, engineers design pumps and propellers to avoid cavitation so that they do not become damaged.

I already mentioned that you can often observe cavitation behind a rapidly rotating propeller.  Interestingly enough, you can see it in nature.  Look at rocks in a fast flowing stream where the water is flowing particularly fast (such as right before a waterfall) and look for bubbles.  Those bubbles are caused by natural cavitation.

Cavitation is generally not a concern for most building designs, but engineers do consider velocity in water pipes when selecting sizes in order to avoid excess noise and damaging wear and tear. If you are seeking to work with an engineering firm that is client-centered and strives to provides services that are on time, on budget and exceed expectations, please contact us. We would love to work with you on your next project!