Preliminary Design ReviewC09012

Anchorage, AK

Mike DeMayo – Foundation Engineer

Jason Baker – Architectural Engineer

Phil Lazeski – Structural

Abiy Abebe – Fluid Systems Engineer

Chuck Nwapa – Building Thermal Engineer

Josh Sharaf – Thermal System Engineer

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Agenda

1. Foundation Design

2. Architectural – Floor Plan

3. Structural – Roof Truss Design

4. Fluid System Design

5. Building Thermal – Wall Design

6. Thermal System Design

•Design features required for a basement in Anchorage.•Heated foundation walls and floor.•Design must be flexible to accommodate severe thermal stresses.•Summer construction is required to work with the ground when its not frozen.

Home Foundation Details •Cold climate demands specific foundation design.•Most homes in Alaska do not have a basement due to permafrost conditions that are not conducive to construction.•Anchorage has a milder climate than other Alaskan cities.

Home Foundation Details •Types of foundations•Poured concrete•Block foundations

•Poured foundations•More flexible designs•Initially easier to protect against leaks because it is a single sheet•Able to incorporate a heating system to heat FDN walls•Less labor involved in construction

•Block Foundations•Consists of bricks fit together with mortar•More labor to assemble•Able to flex more with thermal stress•Harder to design a custom shape

Available Options for Anchorage Alaska

Frost line and potential permafrost locations determine whether a basement or foundation slab can be applied.

•If building location is perma-frosted it is likely that only a slab for the home can be built•Otherwise, basements can be built during the warm part of the year when digging is possible.•Some homes use heated foundation walls to create an artificial non-frosted ground layer around the foundation

Functions of Basement•Support house•Be accessible from outside and inside the house•Store solar hot water tanks and auxiliary heating systems•Insulate home from potentially frozen ground

Lightweight concrete Heavyweight Concrete

Compressive Strength (psi) 4350 Up to 19000

Density (lb/in^3) .0343 .235

Which concrete is best?

*Concrete must provide a factor of safety between 4-6 for the 2200 ft^2 house.**Ave. weight of 2200 ft^2 is 60 psf for the first floor and 40 psf for the first floor

http://en.allexperts.com/q/Building-Homes-Extensions-2333/House-weight.htm

Concrete Details•Alaskan building code requires basement walls to be reinforced with rebar to counteract the force from the existing soil onto the walls of the foundation

Total weight of house is approximately 110000 lbs.Rebar-ed concrete has compressive strength of about 4000 psi.To support the house the walls need to be 8.5 - 9 inches thick to account for a factor of safety of 5.

Basement Design•Grade of hill has some advantages and disadvantages•Allows for outdoor access to basement•Requires excavation to existing ground to allow foundation to sit flush with the ground.

Brown filling indicates ground that needs to be removed.Ground may also need to be removed on the lower side to allow the south footing to be below the frost line.

Basement Design Drawing

*Door faces South, towards lower part of slope

Preliminary general arrangement of basement, including outdoor access door and hot water tank storage.

Load bearing wall is located on the soil-side wall to help brace against the force of the outside soil.

Ground Floor

Second Floor

Roof Truss Design• House Dimensions – 25’ x 44’• 25’ span + 1’ overhang both sides, 27’ truss• 23 Structural trusses + 2 for overhang both sides

• Spacing – 24” on center• 4/12, 6/12 common 12/12 optimal insolation• Snow = 12.5 lbs/ft3, 70.6” avg. yearly snowfall• Apply standard truss designs, common building

materials, and static analysis.• Factor of safety 4-6 times

• Example of standard 4/12 pitch Howe truss capable of spanning 24’ - 36’ using 2”x4” members.

Roof Truss Design

Truss information from:

http://www.troutcreektruss.com/Products/Engineered-Roof-Trusses.php

• Backup water heater is necessary because of low average peak sun-hours in Anchorage

• Must circulate an antifreeze fluid through collectors (e.g. glycol water solution)

• Drainage system to drain fluids during no-use period

• System Parameters

Hydronic System

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Glycol disrupts hydrogen boding when mixed with water therefore lowering the freezing point

General schematic of system

• 120 gallon storage tank to ensure enough hot water is available

• Double-walled heat exchanger inside tank to prevent contamination of fluid

• Controller to activate/deactivate the pump when appropriate temperature difference is reached

• Valves for maintenance purposes

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Analysis of head that needs to be overcome

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Pump Options

• Small Solar Hot Water Pump: The circulator pump measures the temperature of your hot water at the outlet of your storage tank and the inlet of the Solar Hot Water Collector. The Standard Solar Hot Water Controller is designed to handle a system made of two SunMaxx Solar Collectors (Flat Plate or Evacuated Tubes), and is generally more than enough to handle most small to medium-sized residential applications; 1 to 2 people

• Our Price: $85.16Specifications:Flow Range: 0-18 GPMGPM

• Head Range: 0-9.5 ft

• Minimum Fluid Temperature: 40 F (4 C)Maximum Fluid Temperature: 230 F (110 C)Connections: 3/4, 1, 1-1/4, 1-1/2 inWeight: 12 lbsMaximum Collectors In-Line: 2 SunMaxx 20 or 25 collectors

Extreme-Head Compact Bronze Turbine-Style Centrifugal Pumps

• With a turbine-style impeller, these pumps generate 10 times the pressure of a standard centrifugal pump at the same diameter and speed. These have a much smaller footprint compared to multistage pressure-boosting centrifugal pumps. Great for debris-free applications with chillers, heat exchangers, and boiler feed systems. Both housing and impeller are bronze. Pumps are not self-priming—they must be placed at or below the level of liquid being pumped. Do not run dry or against a closed valve. Do not use with solids. Motors are open dripproof (ODP), continuous duty, and have thermal overload protection (unless noted). Single-phase motors have screw terminals; three-phase motors have 4" wire leads. Connections are NPT female. Maximum viscosity is 55 centipoise (similar to SAE 10 oil). Temperature range is -20° to +225°  F.

• Price: $565.80• Common Compatible Chemicals Ethylene Glycol, Hydraulic Oil

(petroleum based only), Motor Oil (up to 70° F), Water (up to 180° F)   •  Max. Flow, gpm Max. VAC @  @ 60 ft.@ 115 ft.@ 230 ft.@ 350 ft.ft.

of 60 Hz PipeOverall Size, of Headof Headof Headof HeadHeadhp(phase)AmpsSizeHt. x Wd. x Dp.Each3.43.12.52380 1/3115/208-230 (1)9.6/4.81"6 7/8" x 6 1/2" x 13 5/8

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1ST PROPOSED WALL DESIGN (SECTIONAL VIEW)

THERMAL NETWORK

Table showing Calculated R-Values and total U-value

Assuming temp difference of 20C and with Wall area of (16m^2).Heat

loss is 48.256Watts

2nd PROPOSED WALL DESIGN (SECTIONAL VIEW)

THERMAL NETWORK

Table showing Calculated R-Values and total U-value

Assuming temp difference of 20C and with Wall area of (16m^2).Heat

loss is 45.6848Watts

• Heat Losses calculated are by convection and conduction alone through the wall. Heat loss through windows and cracks are assumed minimal and therefore have not been accounted for.

Solar Thermal Analysis

• Collector Modeled: Heliodyne Inc. Gobi 3366

• Price per unit: $640

• Optical Efficiency (Test Intercept): .734

• 130 ° water temperature

• Area: 26.8 sq feet

• Ideal Angle: 45 °

• 6 Collectors – Parametric Plot

Solar Thermal Analysis (ctnd.)

• Usable – March to September

– At least 80% of hot water from solar energy– June, July – 100%– .7-.8 Optical Efficiency

• Alternatives– SKN 3.0 – Better Optical Efficiency– Solar Energy, Inc SE-28 – Greater Area

Solar Collector Seasonal Use

Parametric Plots – Collector Slope, Number of Panels