| 862521. |
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| 862522. |
- Lazzarotti, Valentina, et al.
(författare)
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Openness and innovation performance: an empirical analysis of openness determinants and performance mediators
- 2017
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Ingår i: European Journal of Innovation Management. - 1460-1060 .- 1758-7115. ; 20:3, s. 463-492
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Focusing on some relevant constructs defined by the open innovation (OI) literature (i.e. determinants of openness; openness choices operationalized in terms of collaboration depth with scientific and business partners; organizational and social context; innovation performance in terms of novelty and efficiency), this paper investigates the relationships among such constructs. More specifically, the purpose of this paper is to empirically analyse two types of relationships: between some contextual factors and firms’ openness choices; and among openness choices, a set of organizational-managerial and social factors, and OI performance outcomes.Design/methodology/approach The authors carried out a theory testing survey, involving four European countries (Finland, Italy, Sweden and the UK). The authors applied descriptive statistics and a series of regressions.Findings The authors analysed the impact exerted by external and internal variables on the collaboration depth with scientific and business partners: technological trends are relevant to move firms towards external collaborations, with both types of partners; efficiency goals pursued in collaborations are related to the collaboration depth with both types of partners, while an aggressive innovation strategy is positively related only to scientific-partner depth. Besides, collaboration depths with both partners are positively related to the both sides of innovation performance (i.e. novelty and efficiency), but the organizational-managerial and social contexts emerge as relevant mediator variables. Organizational-managerial and external relational social capital exert a beneficial role on the both types of innovation performance, while internal relational social capital benefits only novelty.Research limitations/implications The work shows important limitations such as the low level of the explanatory values in the regression models. Therefore, the results must be considered as preliminary explorative insights that may be useful to encourage further studies.Practical implications This work serves to raise managers’ awareness on the opportunity of developing organizational-managerial mechanisms, as well as on the importance of social capital to profit from collaborations.Originality/value Although during the last decade many researchers have claimed that we are in the era of OI, empirical works, which provide both a more comprehensive and detailed understanding of the phenomenon, are still few. Moreover, the specific action of the context (managerial, organizational and social) as possible mediator of the performance outcomes of openness is empirically under-studied. The authors’ work attempts to fulfil these gaps.
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| 862523. |
- Lazzarotto, Alberto, 1984-, et al.
(författare)
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A methodology for the calculation of response functions for geothermal fields with arbitrarily oriented boreholes : Part 2
- 2016
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Ingår i: Renewable energy. - : Elsevier. - 0960-1481 .- 1879-0682. ; 86:01, s. 1353-1361
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Tidskriftsartikel (refereegranskat)abstract
- In the modeling of shallow geothermal systems, the accurate representation of the borehole field configuration is important for a proper estimation of the long term thermal behavior of borehole field systems. Modeling tools based on the so-called g-functions method, utilized for the design of borehole fields, assume that boreholes are vertical. This is a limitation since this condition might not apply in a real installation. This paper is focused on the calculation of g-functions of borehole fields featuring non-vertical boreholes. The strategy utilized consists in representing the boreholes as stacked finite line sources. The temperature along these finite lines, can be calculated by superposition of the effects of each linear heat source in the field. This modeling technique allows to approximate uneven heat distribution among the boreholes and along the axis of each individual borehole. This is a required feature for the calculation of g-functions according to Eskilson's boundary conditions. The test cases presented show that the method yields results that are compatible with the expected physical behavior of the system, and similar to previous results by Eskilson. The computational performance achieved indicates that the method proposed could be potentially utilized during the design phase of these systems.
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| 862524. |
- Lazzarotto, Alberto, 1984-
(författare)
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A methodology for the calculation of response functions for geothermal fields with arbitrarily oriented boreholes : Part 1
- 2016
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Ingår i: Renewable energy. - : Elsevier. - 0960-1481 .- 1879-0682. ; 86, s. 1380-1393
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Tidskriftsartikel (refereegranskat)abstract
- This article is part of a two paper series presenting a development in the methodology for the calculation of response functions for geothermal fields with arbitrarly oriented boreholes. In the method utilized, boreholes are represented as sets of stacked line sources and the borehole temperatures are calculated by means of a superposition procedure. This particular paper is focused on the efficient computation of the building block of this approach, which is the non dimensional mean temperature response g~(t) along a finite line due to a step heat injection along a second finite line, where the lines are arbitrarily oriented. The speed in computing this function is critical for the applicability of the method. The solution proposed to achieve the required performance is a hybrid approach involving analytical, numerical and implementation aspects: an analytical procedure to simplify the expression of g~(t) was developed, the resulting problem was solved with a tailored numerical method, and the algorithm was implemented using a high-performing programming language. Each of these aspects showed to have a great impact from a performance perspective. The performance achieved in the calculation of g~(t) enables the integration of this method within the scheme utilized for g-functions calculation.
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| 862525. |
- Lazzarotto, Alberto
(författare)
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A network-based methodology for the simulation of borehole heat storage systems
- 2014
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Ingår i: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 62, s. 265-275
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Tidskriftsartikel (refereegranskat)abstract
- The optimization of strategies to operate borehole thermal energy storage systems can play an important role for the exploitation of this technology. Available tools utilized for the design of borehole fields don't consider these aspects in the calculation. For this reason a network-based methodology which gives a sufficient level of detail to describe different system operation strategies has been developed. In particular, the method allows to calculate how the heat is distributed among the borehole heat exchangers in the field according to the way the brine is supplied to the borehole heat storage system. This enables to test the same borehole field configuration pattern for different piping arrangement. An example of application where a simultaneous need of heating and cooling is met by extracting and injecting heat in different region of the ground storage is considered to illustrate the potential of the method.
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| 862526. |
- Lazzarotto, Alberto, et al.
(författare)
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Analysis and modeling of a large borehole system in Sweden
- 2016
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Konferensbidrag (refereegranskat)abstract
- This paper presents a study on the thermal simulationof a large existing borehole thermal energy storage(BTES) system located in Stockholm, Sweden. Thebore field investigated presents an uneven pattern,which comprises vertical and inclined boreholes, for atotal of 130 units. Such complex bore field geometrycannot be modeled with the current availablecommercial design tools. The test case presented isutilized to explore the influence of boundaryconditions and level of detail utilized for representingthe model geometry on the output of the simulation.Two boundary conditions and three geometricalconfigurations were studied. The results show that, inthe considered case, the results obtained with thetested models give a marginal difference, hence alsothe greatest level of simplification can be utilizedwithout loosing accuracy in the analysis.
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| 862527. |
- Lazzarotto, Alberto
(författare)
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Developments in Ground Heat Storage Modeling
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ground heat storage systems can play an important role for the reduction of green house gases emissions by increasing the exploitation of renewable energy sources and “waste heat” with a consequent diminution of the use of fossil fuels.A ground heat storage consists in an array of vertical boreholes placed in such a way that promotes the mutual thermal interaction between the ground heat exchangers creating the necessary conditions required to effectively store and retrieve heat. Suitable modeling tools for the estimation of the thermal behavior of these systems are very important to build installations yielding economical performance compatible with what expected during the design phase.This thesis aims at giving a contribution in the development of the thermal modeling of borehole heat storage systems. The main objective is introducing in the modeling process a few features that are not usually considered in state of the art models, with the goal of improving the representation of the physical phenomena. These features are the mathematical description of the topology of the borehole heat exchangers network, and the modeling of borehole fields with arbitrarily oriented boreholes.The detailed modeling of the topology of the borehole heat exchangers is approached with a network model. The overall geothermal system is discretized into smaller systems called components. These are linked between each other in a network fashion to establish the logical relations required to describe a given boreholes connections arrangement. The method showed that the combination of a sufficient level of discretization of the system and of a network representation yields respectively the granularity and the flexibility required to describe any borehole field connections configuration.The modeling of non-vertical borehole fields is approached by developing a method for the calculation of g-functions for these configurations. The method is an extension of a recent work done by Cimmino on the computation of g-functions for vertical borehole fields. This modeling technique is based on describing boreholes as sets of stacked finite line sources and on the superposition principle. This approach requires the computation of response factors relative to couples of finite lines. A procedure for the fast computation of these response factors for the case of arbitrarily oriented lines is given. This yields computational performance that guarantees the practical feasibility of the methodology.The last part of the thesis deals with the modeling of the storage system from a broader perspective. The borehole field is considered as part of a larger system constituted by several interacting components (i.e. heat pump, building, etc.). Interactions play a key role in the resulting overall performance of these systems. The analysis of the mutual relations between building envelope and borehole field design is utilized as an example to highlight advantages and challenges of strategies yielding a more integrated design.
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| 862528. |
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| 862529. |
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| 862530. |
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