Nelson Mechanical Design Martha's Vineyard Green Contractor
  NEW! Contractor of the Year Award
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  NEW! Harmon Pellet Powered Boilers & Furnaces
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  Mansion House Goes Green with Geothermal
  NMD National Award
  Daikin Altherma Heat Pumps
  ENV Remote Home Control
  LEED for Homes Residence
  Net Zero Home, Longview
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  Geothermal Heat Pumps
  Air to Water Heat Pumps
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  Solar Thermal
The NMD Testing Lab
Twenty Panel Solar Hot Water
Atria Restaurant Solar
Geothermal / Solar Hybrid
Ocean-front Geothermal Concept
Pond-Based Geothermal Concept
  Residential
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  Hot Water Heating
  AquaPex
  Clivus Composting Toilets
  Custom Plumbing Solutions
  Fixtures
  Hot Water Boilers
  Radiant Floor Heating
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  Hydro Air Systems
  Multi Aqua Systems
  Ducted Systems
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  Fresh Air Exchange
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Schematics and Specs
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Copyright ©2005-2010
Nelson Mechanical Design
All rights reserved.
NMD is Martha's Vineyard's Premier Mechanical Design Firm
We provide professional and innovative service combined with experience

We have built our mechanical contracting business on the foundation of our mechanical design abilities. This is one of our favorite services to offer - from start to finish we can calculate and specify exactly what your home or building requires to be comfortable and efficient. Mechanical systems will not operate at their highest efficiency when they are sized for a building on guesswork or "the way we have always done it".

Instead, we follow the steps outlined in The Process to develop a scope of the project and determine the direction for the design process. We then apply appropriate software tools to help us create the system model that will lead to an initial mechanical design. The energy use projections from our software models aid us in the selection of the components and systems that result in the final mechanical system. Sound practice is followed as we assess the needs of the client, structure, and energy budget. Usually several options are developed as we proceed with the design; ultimately the final system comes together as overall performance issues are reviewed.

We are then able to proceed with the installation; confident in the expected performance, energy efficiency, and expected payback.

Some of our software tools include:

Elitesoft RHVAC: Elitesoft AUDIT:
This heat gain/loss program allows us to input a building envelope and determine the heat loss and gain for the structure. A huge variety of windows, doors, wall types, floor types, roof types, and insulation components are available to create a computer model of any building shell. Once the building is drawn in the program, it can be rotated to optimize solar gain or loss to maximize solar heating or minimize cooling costs. Any component of the structure can be adjusted or changed to determine its overall contribution to energy loss or gain. For example, window choices and levels of window coatings, screening, and shading can be made based on their energy performance - giving the client a real economic analysis of the costs and benefits of different windows. This program can also perform infiltration and ventilation analysis, particularly important with today's tighter building envelopes The heat loss and gain numbers developed in the RHVAC can be hot linked to the AUDIT program. Different mechanical systems can be created and their yearly energy use projected. We can compare a propane fired boiler with a propane fired furnace with a geothermal heat pump and get yearly performance numbers for all of them. We can also input domestic hot water usage, appliance usage, laundry loads per year, the cost of utilities to run these loads, and the yearly cost with adjustable inflation. This is a very powerful tool in conjunction with RHVAC to determine the payback period and savings of any mechanical system
Elitesoft DUCTSIZE: HVACSolution/Taco HSS:
This program is also linked to RHVAC; using the heat loss and gain numbers it helps us develop forced air systems that will meet the structure's heating and cooling needs. Trunk sizes, air velocity, and diffuser and grille constraints can be input to show how architectural changes can impact system performance. This program is used to develop and size hot water heating systems. We have used it to confirm the engineering of geothermal, propane and oil fired boiler, and solar heating systems. It also assists us in choosing the most efficient circulators to reduce the total energy use of the mechanical system.
Retscreen: Heatcraft Coilcalc:
This software suite was developed by NASA and the Canadian Department of Energy to model solar and wind power installations and generate payback projections. Using input weather data, project location and orientation, projected demand, monthly usage, and storage capacity, this program will generate a typical solar energy collection figure, suggested system sizes, and a payback projection. It is generally recognized as fairly conservative so we have confidence in using the numbers generated to create payback periods and system costs. This program has been instrumental in the engineering required for our custom hydronic coils. We were able to determine the most effective water temperature to maximize heat output in forced air systems for solar and geothermal installations. Once the design is complete, this program will generate drawings and specs necessary to order these custom hand made hot water coils.
TacoNet: ASHRAE Handbook:
We use this program to assist us in the selection of our circulators used in heating and cooling systems. We can use head loss and flow requirements of heating systems generated in our HVAC Solution program to find the best circulator to fit. The American Society of Heating, Refrigeration, and Air Conditioning Engineers is leading the green building engineering world in the development of standards and goals for sustainable design. Their handbooks and code handbooks often provide us with answers to our mechanical system questions - engineering and installing systems to their standards guarantees a high level of system performance and efficiency
WattsRadiant Radiant Works: FlatPlate Select:
We use this program to model radiant floors in different structures over different floor covers and types. The flexibility of this software allows us to project for the client, architect, and contractor the success of different radiant floor installations and minimum system requirements
We use this program to model the geothermal heat pumps used in our hot water heating system designs. We have optimized circulator sizes that move hot water through heat pump flat plate heat exchangers to ensure optimum performance and minimum lifetime energy use
While Brian Nelson has received his Masters Degree in Mechanical Engineering (1997, Boston University), he is not a licensed professional engineer. We are offering mechanical design services and do not provide plans or drawings carrying the seal of P.E.