hvac project

20-May-14 HVAC & R

HVAC&R Refurbishment Project (Passive House in Freiburg)

“New facade in passive house standards, supply and exhaust

ventilation with MVHRS”

“Floor Heating/Cooling using RGSHP”

Participants:

Vahid Gerami

Hazal Yakut

Mahmoud Eid

Hochschule Offenburg University of Applied Sciences

Contents

• Retrofit Project

• Why does my concept make the building a ”Better Building” ?

• Project Background

• Motivations

• Introduction

• RGSHP

• Floor Heating

• MVHRS

• Facade Engineering

• HAP 4.41 Calculations

• Project block diagram

20-May-14 HVAC & R 2


Retrofit Project

Introduction

• The term passive house (Passivhaus in

German) refers to the rigorous, voluntary,

Passivhaus standard for energy efficiency

in a building, reducing its ecological

footprint. It results in ultra-low energy buildings that require little energy for

space heating or cooling.


• One of the original 1990 Passive Houses,

located in Darmstadt, Germany.

• Passive design is not an attachment or supplement

to architectural design, but a design process that is

integrated with architectural design. Although it is

mostly applied to new buildings, it has also been

used for refurbishments.

http://en.wikipedia.org/wiki/File:Passivhaus_Darmstadt_Kranichstein_Fruehling_2006.JPG

http://en.wikipedia.org/wiki/File:Passivhaus_thermogram_gedaemmt_ungedaemmt.png


Retrofit Project

Building layout


Office building, consists of 6 floors with total

area of 3042 m².

Central heating with Oil-fired boiler distributed

in each office by thermostatically-controlled Radiators.

No cooling. Manually controlled internal

shading devices plus heat gains for typical

office.

No ventilation systems. Manually controlled

window opening.

Manually controlled ligting. Fluorescent tubes lighting.


Retrofit Project

Floor plan of the building



Why does my concept make the building a ”Better Building” ?

Motivations


• Increase of primary energy usage in Germany.

• World’s aspirations towards green energy utilizations.

• Rising demand of efficiency.

• Growing share of Renewable Energies.

• Variation of consuming tarrifs depending on the share of

Renewable Energies and various CO2 emissions.



General Requirements for Passive House

• The Passive house standard for central Europe requires that the building

fulfills the following requirements:

• The building must be designed to have an annual heating demand as calculated with the Passive house Planning Package of not more than 10

kWh/m² per year (4746 btu/ft² per year) in heating and 15 KWh/m² per year

cooling energy

OR

• to be designed with a peak heat load of 10 W/m²



Retrofit Project

Project Background

New facade in passive house standrads.


New ventilation system using MVHRS.

Floor heating/cooling using RGSHP.


Project Background

Floor Heating/Cooling using RGSHP


Environmental Impact


Introduction

How does RGSHP work ?

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Introduction


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Introduction


20-May-14 HVAC & R 12

A geothermal heat pump moves

heat into or out of the earth using

water wells or a network of high-

density polyethylene pipes buried

in horizontal trenches or vertical

boreholes.

The pipes carry a heat transfer

fluid usually comprised of water

and antifreeze, which is pumped

through the ground loop and

geothermal heat pump units within

the building. The heat transfer fluid

extracts heat (heating mode) from

the earth surrounding the ground

loop.

Indoor Unit

Heat Pump


Introduction


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Introduction


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Introduction

Basic system types

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1.Piping system

2.Heat pump 3.Distribution system

Vertical closed loops

(very common in our case for area limitations)


Introduction

Basic system types

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Concept of Work

Thermal Comfort, Energy efficinecy and Energy usage

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Free Heat Energy stored in Earth (according to Freiburg coordinates (latitude 48.0 deg, longitude

-7.8 deg, elevation 278 m) 11 C° (mean annual air temperature)/6 mdepth ).

High efficiency of HP (w.r.t. DIN V 18599 energy balance concept C.O.P.= 3 – 4).

Simplicity in installation with low life cycle cost.

Life expectancy of 50 years with low maintenance cost and low land area requirement (7 m²/Kw

for horizontal trenches).

Cost payback as short as 5 to 7 years with great occupant comfort.

Safe, hygienic, noise-free and stable deep soil temperature.


Concept of Work

RGSHP

Disadvantages

High initial cost for drilling to the

required targeted depth.

High installation cost for the floor

heating system.

GSHP is not feasible in all

locations.

Uncertainty in site conditions,but

soil conditions can vary seasonally.

Need experienced vertical loop

installer, not conventional well driller.

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Concept of Work

RGSHP Requirements

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Vertical closed loop system piping is going to be

used because of our limited area for piping and our

need for a stabilized seasonal ground temperatures.

Loop Lengths

In order to maintain an in-door constant temperature of

28 C° during winter with a design annular wet bulb

temperature of -13.3 C° and summer with a design

annular dry bulb temperature of 32.9 C° in Freiburg, a

Vertical U-tube (1¼ “ Pipe) of high density polyethylene

(HDPE) with a pitch of 2 (Ft. of pipe per Ft. of Bore) and

total trench length of at least 400 Ft. at 2 loops and at

ground depth of 80 Ft. to achieve around 45 C° must be

used and at 200 mm average spacing and flow rate of

32.8 USgpm. (k=1.2 Btu/hr-ft-oF for vertical loops and an

annular fill/grout conductivity of 0.85)

qW flow USgpm = (QW, Btu/hr) / (60 min/hr * ρW lbs/USgal *CP Btu/lb °F * ΔT °F)


Concept of Work

RGSHP Requirements

Heat Pump

The minimum efficiency for water heat pumps rated under ARI Standard

210/240 is 10 Btu/whr. Since water-to-air heat pumps appear to cost more according to the results of the TVA GSHP promotional and the NRECA/UA

study, an efficiency equivalent to a 10 SEER (seasonal energy efficiency ratio)

should at the very least be the minimum required.

A minimum EER of 14 Btu/whr at ISO 13256-1 GLHP conditions (77ºF/25ºC

Entering Water Temperature). Data should be in ARI Directory not in

manufacturer’s literature.

A maximum head loss of 12 ft. of water at 3 gpm per nominal ton.

Extended range capability to operate with an entering liquid temperature of

100oF in cooling and in heating at 32 °F.

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Concept of Work

RGSHP Requirements

In order to arrive at a minimum recommended EER, the performance of a line

of compressor is used as the basis for the design of a 3 ton heat pump.

A set of heat pumps [15 ton capacity (requires a total power ‘for the pump’ of

2400 watts)] must be used to deliver a total cooling load (the max. load in our

case) for the whole building.

Antifreeze solution level

A Propylene solution will be added at 10% by water volume according to

mean annular ground temperature ranges. (Warning more antifreeze will be

required if loops are shorter than recommended)

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Floor Heating

Concept

floor heating and cooling is a type of heating and cooling that controls

indoor climate thermal comfort by the three types of heat transfer

conduction, radiation and convection. Under-floor tubes are the transporter

of the working fluid (e.g., hot water).

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Floor Heating

Types of floor heating systems

Electric system

Hydronic system: A fluid is used in a closed-loops piping, and this is the type used in our concept of floor heating, which is Hydronic radiant type.

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Floor Heating

Thermal comfort quality

ASHRAE has defined the Thermal Comfort as the environment's

conditions in the place where humans are occupying, and it is the

thermal conditions which lead to the comfortability of persons with the

thermal condition in any closed place.

Radiation has a significant impact on the thermal comfort but only in

one case when radiation composes more than 50% of the heat

exchanged between the floor and the rest of the space.

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Floor Heating

Safety

Floor heating with low operating temperatures can be integrated inside the

floor layer or underneath the floor layer. So burn hazards, or any

hazardous conditions for the persons are not possible.

It is very convenient for explosion proof places where electrical devices

cannot be used for safety issues.

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Floor Heating

Indoor air quality

Concerning the indoor air quality and moisture control, floor heating

accommodates conditions that lead to less mold, bacteria, viruses and

dust in the indoor air.

Ventilation, filtration and dehumidification of air can be achieved.

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RGSHP

Radiant Floor Heating Requirements

According to the required cooling and heating loads and using the

predefined floor area of 2433,6 m², the output heating/cooling required

should be around 64 W/m².

At a flux of 64 W/m²; (20 Btu/(h*ft²)), the surface temperature must

be around 92 °F (34 C°).

For a given flux and R-value the closer the spacing the lower the

average fluid temperature should be. (8“ is a good choice)

To achieve around 34 C° a flow rate of 32.8 Usgpm must be used.

At around 405 m² ventilated floor area for only one floor, around

1990 m of tubes should cover the whole floor underground at 8”

spacing.

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Concept of Work

What is MVHRS ?

20-May-14 HVAC & R 28

Heat Recovery Ventilation (MVHRS, HRVS) works by recovering heat

from extract air that would normally be expelled to the atmosphere and

transferring this heat to fresh air being drawn into the property via a heat

exchanger, which the system then distributes throughout.

The system brings ducting to each habitable room and each wet room

within the property. Each wet room is fitted with an extract valve, and each

habitable room with a supply.


Concept of Work


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Energy Saving Recovering the heat from your extract air

instead of simply sending it to atmosphere can lead to

significant energy savings by reducing the cost of your

heating bill.

Whole House Ventilation A Heat Recovery Ventilation

system continually extracts pollutants at their source and

supplies fresh, filtered, warm air to your habitable rooms. This

continual cycle of fresh air movement reduces the relative

humidity in the home and eliminates problems associated

with poor air quality such as condensation and mould growth

Fresh Filtered Air

Quiet Solution Heat Recovery Ventilation systems are

extremely quiet when running, these systems are usually loft

mounted or mounted at high level in a storage cupboard.

High efficiency 85% or higher.

Low cost and simple maintenance.


Concept of Work


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Simplicity is key to a cost-effective installation. To save

on installation costs, many systems share existing

ductwork.

Complex systems are not only more expensive to install,

but they are generally more maintenance intensive and

often consume more electric power.

These types of ventilation systems are still not very

common so only some HVAC contractors have enough

technical expertise and experience to install them.

Duct runs should be as short and straight as possible to

minimize pressure drops in the system and thus improve

performance.

MVHRSs operated in cold climates must have devices to

help prevent freezing and frost formation to avoid the

damage of the heat exchanger.

Precautions

Heat recovery unit


Concept of Work

MVHRS Requirements

With a total required supplied fresh air of 510

m³/hr for only one floor with occupancy of 20

Persons and for the whole office building of 3060

m³/hr, a heat recovery unit could be installed in

suspended ceilings, horizontally in boxing over kitchen cupboards, vertically in a larder unit, or a

utility room or garage and with total capacity of

about 26 tons and average capacity utilization of

0.75, the heat removed from the conditioned space

through unobtrusive white ceiling or wall mounted grilles will be 19 tons.

This air is then directed to the ducting and the long rigid silencer, back to the heat recovery unit.

Before being discharged outside, it passes through

the plate or rotary wheel heat exchanger giving up

its heat to the cold fresh air coming into the house

from outdoors.

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Air handling unit


Concept of Work

MVHRS Requirements

Fresh air intakes will be located away from driveways and laundry and

furnace vents.

A supply inlet will be installed (dedicated inlet or heating register, if

connected to forced air) for each bedroom and one for each common area.

A return outlet will be installed in each high moisture area such as the

kitchen, utility room and bathroom.

Return outlets (pick up points) should be within one foot of ceiling and 10

feet away from an oven or cooktop, as vaporized grease could clog the energy

recovery core.

Duct runs should be kept as short and straight as possible.

Smooth, round ductwork will be used when possible.

intake/exhaust and any ventilation ducts in unheated spaces and seal all joints will be insualted.

A drain to catch any condensate will be installed.

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Concept of Work




Requirements for Passive House

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External shading

To meet the requirements of the Passive house

standard, External shading devices are an effective

way to reduce heat gain through windows in

summer and keep a home cool. They provide much better protection from heat gain than internal

window coverings. External shading reduces heat

gains by 70–85%, whereas internal coverings can

reduce heat gains by as little as 15%. Shading

devices should allow for ventilation on the outside of the window. If shading is fitted too closely to the

window, warm air can be trapped and heat

conducted into the room. Exterior colors reflecting

the sunlight could also be used.

If external shading is not feasible, internal shading

devices such as close-fitting blinds, lined curtains or

internal shutters are preferable to no shading at all.




Advanced window technology

To meet the requirements of the Passive

house standard, windows are manufactured

with exceptionally high R-values (low U-values,

typically 0.85 to 0.70 W/(m².K) for the entire window including the frame). These normally combine triple-pane insulated glazing (with a good solar heat-

gain coefficient, low-emissivity coatings, sealed argon or krypton gas filled

inter-pane voids, and 'warm edge' insulating glass spacers) with air-seals and

specially developed thermally broken window frames.

20-May-14 HVAC & R 35

http://en.wikipedia.org/wiki/File:Passivhaus_Fenster_Beispiele.png


20.05.2014 Mustertext, z.B. Dozent, Veranstaltung, etc. 36


Facade Engineering

Windows

Passive House Current Building

Define new U-Values




Super insulation

• Passive house buildings employ super insulation to significantly reduce the

heat transfer through the walls, roof and floor compared to conventional

buildings.A wide range of thermal insulation materials can be used to

provide the required high R-values (low U-values, typically in the 0.10 to

0.15 W/(m².K) range). Special attention is given to eliminating thermal

bridges.

20-May-14 HVAC & R 37




Facade Engineering

Walls


Define new U-Values




Facade Engineering

Roof


Define new U-Values



Retrofit Project

HAP 4.41 Calculations

Current Building Passive House

Ventilated Floor Area 2433,6 m²

Fresh Air 7,08 l/s/person (≈ 0.45 1/h [ACH])

Cooling Total load kW 188.5 155

Heating Total load kW 154.6 62.6

Cooling and Heating Load

Cooling Total load W/m² 77.45 63.69

Heating Total load W/m² 63.52 25.72


Retrofit Project

Project block diagram

20-May-14 HVAC & R 41

TCL: 188.5 kW

THL: 154.6 kW

TCL: 155 kW

THL: 62.6 kW


Retrofit Project

20-May-14 HVAC & R 42

hvac project

Documents

project building layout

office building

better building

project introduction

passive design

passive house standards

passive house standrads

project floor plan