4. Product design and development
4.2 Scope of product development in the thesis
4.2.1 Process of product development in the thesis:
The client’s requirements were specified as a starting point of product development. Different stakeholders and decision makers had different requirements and wishes for the future product. Each stakeholder had also different relevance in a decision making process. It has shown to be the case that lifetime, space optimization, overall design, and indoor environment were having the highest importance. It is probable that the designed solution would not have a success on the market without meeting the mentioned demands.
The next step in product development was to specify the properties of new product which would ensure that it will work in the way clients require it to work. The design objectives needed to be specified and the objective tree method was used for those purposes. The main aim of objective tree method was to clarify the objectives and their relationship. On the left side of the objective tree are stated product attributes. By working through the objective tree towards the right side, it was explored how the desired product attributes can be accomplished. We are getting from the wishes to the real practical solutions. The lower-level objectives (situated on the right side of Figure 4) are a means of achieving higher-lower-level objectives (situated on the left side of Figure 4). Going from the lower to the higher level of objective (from the right to the left side of Figure 4) one can realize why particular sub-objective is needed for design of the product.
The objective tree method for the new types of cooling, heating, and ventilation systems is depicted in Figure 4.
24
Good indoor environment
Fresh air
Comfortable temperature
Without draft
Quiet operation Health
Productiviy Comfort Good feeling
Ventilation
Heating Cooling
Devices
Low air velocity
Low cost
Low initial cost
Low operational cost
Integrated systems
Low pressure loss
Low heat loss
Long lifetime Dureable materials
Good design
Integrated solution
Evenly distributed temperature
Easy to use
Easy to built Connections
design Low temperature
Low material use
Optimal thermall mass
Environmental
impact Sustainability
Air distribution ATD selection
Material use
Energy efficiency ATD position
In the room
Prefabrication
Heating (cooling) side
Ventilation side
Thermal bridges Ducts in ventilation system
Material of pipes
Plastic
Steel
No disruptions Hidden solution
Space optimization No suspended
ceiling
Control system Easy and logic
Control
Integrated control unit
HOW WHY
Figure 4: Objective tree method
25
The next step after defining the product attributes was to specify the engineering characteristics which will represent those product attributes. It was very important that product attributes were carefully translated into the engineering characteristics, without losing a direction towards required product to be developed.
The basic idea was to come up with all the relevant engineering characteristics which specify all product attributes and can help the engineer to design the best possible solution of required product, therefore satisfy the customer’s needs. The matrix with engineering characteristics standing against product attributes was created and can be seen in Figure 5. The engineering characteristics relevant for heating system are highlighted with green color and for ventilation system with red color (on the left side of the matrix). The influence of each engineering characteristics on each product attributes was specified on scale from positive (green colour), through neutral influence (yellow colour) to negative influence (red colour).
The matrix chart represents the visualisation of the relationship of the customer’s requirements and engineering characteristics, which are the main “tools” engineer is working with during the product development process. As we already know which product attributes have highest importance for the client, we can very much decide on which part of the matrix to focus the most.
Figure 5: Product attributes vs engineering characteristics
The possible solutions were now generated as a result of product development process. The alternative solutions were compared to each other in terms of satisfying customer’s requirements.
Product attributes
Engineering characteristics
Easy to produce Cheap to produce Easy to mount Cheap to mount Environmental impact Low operative cost Long lifetime Good indoor environment Design Space optimization
Evenly distributed surface temperature Low temperature of the surface Low power of the surface Proper connections of the loops High thermal mass
Low energy consumption of the pump Low pressure loss- RHCS
Type material of pipes Low material use_RHCS Air distribution (ATD selection) ATD position in the room Low pressure loss- DCV Low material use_DCV Prefabrication
Integrated system Low heat loss Low thermal bridges Proper control system Energy efficiency
26
Proposed solution for cooling is based on a fully prefabricated complete wall sandwich element with integrated heating and cooling systems based on plastic capillary tubes casted into the inner layer of high performance concrete, see Figure 11. Proposed solution for ventilation is based on diffuse ceiling inlet made of perforated gypsum boards installed in suspended ceiling, see Figure 22 and Figure 23. The system of diffuse ceiling inlet is designed as integrated part of building. Whereas radiant cooling system based on plastic capillary tubes is designed as integrated part of building component.
The solution for a diffuse ceiling inlet as an integrated part of building component was also designed, but was not approved for further development by company Connovate A/S. The origin of this solution is in ceiling cooling element depicted in Figure 6, which has concrete ribs inside the element. The idea for an element with a diffuse ceiling inlet was to move the ribs out of the element, more precisely at bottom side of element, see Figure 7. The space between neighboring ribs was covered with use of perforated gypsum boards. The resulting space called plenum is used for distribution of inlet air within the element. The resulting ceiling element with a diffuse ceiling inlet can be seen in Figure 8. The plastic capillary tubes were cast into the concrete layer situated in the plenum and incoming air could be therefore precooled or preheated depending on the current needs.
Figure 6: Ceiling cooling element made of high performance concrete
Figure 7: Creation of space for plenum between the exposed ribs
27
Figure 8: A diffuse ceiling inlet as building component made of high performance concrete
The solution for diffuse wall inlet was also designed in similar way as previous solution and is shown in Figure 9. The difference is in depth of the plenum dependent on the size of the used ribs. Similarly as previous case also this solution was not approved for further development. In both cases only part of ceiling/wall area can be activated for ventilation as it is divided by the ribs.
Figure 9: Diffuse wall inlet
28